Phytochemistry and bioactivity of Pedicularis sibthorpii growing in Iran

Phytochemistry and bioactivity of Pedicularis sibthorpii growing in Iran

Laleh Khodaie^I,II; Abbas Delazar^I; Farzane Lotfipour^I; Hossein Nazemiyeh^I; Solmaz Asnaashari^I; Sedighe B. Moghadam^I; Lutfun Nahar^III; Satyajit D. SarkerIV,^*

^ISchool of Pharmacy and Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

^IIBiotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

^IIILeicester School of Pharmacy, De Montfort University, England, UK

^IVDepartment of Pharmacy, School of Applied Sciences, University of Wolverhampton, England, UK

ABSTRACT

The methanol extract of the aerial parts of the medicinal plant Pedicularis sibthorpii Boiss., Scrophulariaceae, growing in the Azerbaijan province of Iran, was found to be active in the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and the antibacterial agar well diffusion assays, but no general toxicity was observed in the brine shrimp lethality assay. A combination of solid-phase extraction (SPE) and preparative reversed-phase high-performance liquid chromatography (prep-RP-HPLC) analyses of the methanolic extract afforded three phenylethanoids (verbascoside, martynoside and isomartynoside), an iridoid (aucubin), a flavonoid (luteolin 7-O-β-D-glucopyranoside) and mannitol, and the structures of these compounds were elucidated unambiguously by spectroscopic means. The distribution of the isolated compounds within the genus Pedicularis has also been discussed.

Keywords:Pedicularis sibthorpii, free-radical-scavenger, antimicrobial, brine shrimp lethality, iridoid, phenylpropanoid, flavonoid

Introduction

The family Scrophulariaceae incorporates ca. 400 genera and 4500 species (Maia et al., 2000). The genus Pedicularis L., comprising about 500 medicinal herbs, mostly endemic to China, is one of those genera of this family (Zhang et al., 2011). Several species of this genus, e.g., P. muscicola, P. oliveriana, P. kansuensis and P. rhinanthoides, are used in Tibetan medicine system (Jiang et al., 2003; Zhang et al., 2011). Traditionally, many Pedicularis species have long been used in the Traditional Chinese Medicine (TCM) as a cardio-tonic, to improve blood circulation, and for the treatment of exhaustion, collapse, senility and digestive problems. It is effective in relieving uneasiness of body and mind (Jiang et al., 2003; Zhang et al., 2008). Some species of the Pedicularis are also used in the treatment of malignant sores (Shi et al., 1999). To the best of our knowledge, while the only previous phytochemical studies on P. sibthorpii revealed the presence of phenylpropanoid glycosides (Eribekyan et al., 1991), the volatile oil of this species has recently been investigated (Khodaei et al., 2012). However the extracts of P. sibthorpii have never been evaluated for their biological activities. As part of our on-going phytochemical and bioactivity studies on Iranian medicinal plants (Delazar et al., 2004, 2006, 2007, 2009, 2010a,b; 2011a,b; 2012; Babaei et al., 2008; Nazemiyeh et al., 2008a,b, 2011; Nazifi et al., 2008; Razavi et al., 2008, 2011; Modaressi et al., 2009; Asnaashari et al., 2010; Pasdaran et al., 2012), we now report on the bioactivity of the extracts of P. sibthorpii Boiss. growing in Iran, and the isolation and identification of three phenylethanoids [isomartynoside (3), martynoside (2), and verbascoside (1)], an iridoid (aucubin, 4), a flavonoid (luteolin 7-O-β-D-glucopyranoside, 5) and mannitol (6) from the methanolic extract of this species. The distribution of the isolated compounds within the genus Pedicularis has also been discussed.

Material and Methods

General

NMR spectra were obtained using a Bruker Spectrospin 200 NMR-spectrometer. Chemical shifts are given on δ (ppm) scale with TMS as the initial standard. UV-visible spectra were recorded using a Shimadzu-1600 spectrophotometer. Preparative HPLC was conducted on a Knauer-1800 prep-HPLC coupled with SPDM photo diode array detector (detection at 220 and 280 nm).

Plant material

Aerial parts of Pedicularis sibthorpii Boiss., Scrophulariaceae, were collected during the flowering stage from Lighvan region of the East Azerbaijan province in Iran in May 2008. A voucher specimen (TUM-ADE-0318) for this collection has been deposited at the Herbarium of the Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.

Extraction

Air-dried and ground aerial parts of P. sibthorpii (200 g) were successively Soxhlet-extracted using n-hexane, dichloromethane (DCM) and methanol (MeOH) (1.1 L each). All these extracts were separately concentrated under vacuum by rotary evaporator not exceeding the temperature of 50 ºC, yielding 2.2 g, 1.7 g and 13.8 g of the extracts, respectively.

Fractionation of the methanolic extract

A portion of the dried MeOH extract (2 g) was fractionated by solid-phase-extraction (SPE) on Sep-Pak (C₁₈, 10 g cartridge) using a step gradient of MeOH-water mixture (10:90, 20:80, 40:60, 60:40, 80:20 and 100:0), 200 mL each. All SPE fractions were dried using a rotary evaporator at a temperature not exceeding 50 ºC.

Isolation of compounds

The SPE fractions (10, 20, 40 and 60% MeOH in water) were subjected to repeated preparative reversed-phase HPLC (prep-HPLC), conducted on a Knauer HPLC (preparative pump 1800), fitted with a Reprosil 100 C18 (250 mm length, 20 mm i.d, particle size 10 μm, Dr. Maisch, Germany) column. The mobile phase consisted of (A) MeOH and (B) water. The following mobile phase programme was used over 32 min to isolate aucubin (4, 3.9 mg, t_R = 18.12 min) and mannitol (6, 169.2 mg, t_R = 7.1 min) from the 10% SPE fraction: 10% A initially, changed to 40% A in 20 min, ran for 5 min, changed back to 10% A in 2 min and maintained there for 5 min. A similar programme over a run time of 55 min was applied for separating verbascoside (1, 8.0 mg, t_R = 27.7 min) from the 20% SPE fraction: 10% A, changed to 80% A in 45 min, changed back to 10% A in 5 min, and stayed there for another 5 min. Similarly, the following programme was applied to isolate luteolin 7-O-β-D-glucopyranoside (5, 6.2 mg, t_R = 29.0 min) from the 40% SPE fraction: 35% A initially, changed to 50% A in 50 min, maintained there for 5 min, changed to 100% A in 3 min, maintained there for 7 min, changed back to 35% in 3 min, and kept there for 7 min. The 60% SPE fraction was analysed by the following mobile phase programme: 40% A initially, changed to 100% A in 38 min, maintained there for 20 min, changed back to 40% A in 7 min, and maintained there for 5 min, to isolate martynoside (2, 3.5 mg, t_R = 22.0 min) and isomartynoside (3, 3.6 mg, t_R = 23.0). Photodiode array (PDA) detector was used to monitor the chromatogram, and the HPLC separation was carried out at room temperature. The flow rate was 8 mL/min and the injection volume was 1 mL. The structures of the compounds were determined by spectroscopic means as well as by comparison with the literature data of respective compounds.

Verbascoside (1): Brown amorphous solid. UV, ¹H NMR (200 MHz, CD₃OD) and ¹³C NMR (50 MHz, CD₃OD) data were in agreement with the published data (Nazemiyeh et al., 2008c; Delazar et al., 2005, 2012).

Martynoside (2): Pale brown amorphous solid. UV, 1H NMR (200 MHz, CD₃OD) and ¹³C NMR (50 MHz, CD₃OD) data were in agreement with the published data (Toth et al., 2007).

Isomartynoside (3): Brown amorphous solid. UV, ¹H NMR (200 MHz, CD₃OD) and ¹³C NMR (50 MHz, CD₃OD) data were in agreement with the published data (Calis et al., 1984).

Aucubin (4): White amorphous solid. UV, ¹H NMR (200 MHz, CD₃OD) and ¹³C NMR (50 MHz, CD₃OD) data were in agreement with the published data (Bernini et al., 1984; Rønsted et al., 2000).

Luteolin 7-O-β-D-glucopyranoside (5): Yellow amorphous solid. UV, ¹H NMR (200 MHz, CD₃OD) and ¹³C NMR (50 MHz, CD₃OD) data were in agreement with the published data (Mabry et al., 1970; Suntar et al., 2012).

Mannitol (6): While amorphous solid. ¹H NMR (200 MHz, CD₃OD) and ¹³C NMR (50 MHz, CD₃OD) data were in agreement with the published data (Bock & Pedersen, 1983; SDBS database, 2012).

Free-radical-scavenging activity: the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay

The free-radical-scavenging effect of the extracts and fractions was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay (Kumarasamy et al., 2002, 2007). DPPH was obtained from Fluka Chemie AG, Bucks and a solution of DPPH (0.08 mg/mL) in MeOH was used. Dilutions were made to obtain concentrations of 5 × 10-1, 2.5 × 10^-1, 1.25 × 10^-1, 6.25 × 10^-2, 3.13 × 10^-2 and 1.56 × 10^-2 mg/mL. Diluted solutions (1 mL each) were mixed with DPPH solution (1 mL) and allowed to stand for 30 min for any reaction to take place. The UV absorbance was recorded at 517 nm. The experiment was performed in triplicate and the average absorption was noted for each concentration.

The agar well diffusion assay

Bacterial cultures of Gram-negative species Pseudomonas aeruginosa (ATCC 9027), Escherichia coli (ATCC 8739), Salmonella paratyphii (ATCC 4420), as well as Gram-positive species namely Staphylococcus epidermidis (ATCC 12228), Bacillus cereus (ATCC 9372), Staphylococcus aureus (ATCC 6538), Micrococcus luteus (ATCC 10240), and a fungus (Candida albicans) strain were used to evaluate antimicrobial properties of the methanolic extract. The bacterial strains in lyophilized form were purchased from the Institute of Pasteur, Tehran, Iran. Centrifuged pellets of bacteria and fungus from 24 h cultures were mixed with sterile distilled water, and the turbidity was corrected by adding sterile distilled water until 0.5 McFarland’s turbidity standard [10⁸ colony forming units (CFU) per mL] was obtained. Then these inocula were used for seeding the Muller Hinton agar (Merck). Autoclaved Muller Hinton agar medium was allowed to cool down. Then it was seeded with 10 mL of prepared inocula (10⁶ CFU per mL). The antimicrobial activity of test samples was monitored using the agar well diffusion method (Perumal et al., 1998; Essawi & Srour, 2000; Aqil & Ahmad , 2007), which is a highly recommended method for routine assessment of preliminary antimicrobial screening. Using the Muller Hinton plates, inoculated with a 0.5 McFarland’s standard of selected bacteria, five wells for test samples, two for solutions of extract and different fractions, and one for vehicle control (DMSO), were applied to each Petri dish. For incubation and analysis, 100 µL of test solution was poured by micropipette into respective wells (200 mg/mL). Petri dish was incubated at 37 ˚C. After 24 h of incubation, diameter of the clear zones, showing no bacterial growth, around each well (excluding well diameter) was measured with the help of venire callipers. Plates were prepared in triplicate for each sample. Extracts and fractions that showed significant antibacterial activity at this concentration were further assessed for determination of their minimum inhibitory concentration (MIC). Serial two-fold dilutions of fractions were prepared in broth. Cultures containing only sterile nutrient broth, which did not influence bacterial growth, were used as controls. To each test tube an equal volume of the adjusted inocula was added. After incubation at 37 ºC for 24 h the MIC was read. The minimal inhibitory concentration (MIC) was defined as the lowest concentration of a fraction which was able to completely inhibit the growth of each microbial strain (Bussmann et al., 2010).

The brine shrimp lethality assay

The method described by Meyer et al. (1982) was adopted to study the general toxicity of the plant. Brine shrimp (Artemia salina) was purchased from Water Life, Middlesex, UK. The eggs were hatched in a conical flask containing 300 mL of artificial seawater made by dissolving NaCl in distilled water. The flasks were well aerated by the aid of an air pump, and kept in a water bath at 29-30 ºC. A bright light was left on. The nauplii hatched within 48 h. The n-hexane, DCM and MeOH extracts and SPE fractions were dissolved in 5% DMSO to obtain a concentration of 1 mg/mL each. These were serially diluted two times and seven different concentrations were obtained. A solution of each concentration (1 mL) was transferred into clean sterile universal vials with a pipette and aerated sea water (10 mL) was added. About ten nauplii were transferred into each vial by the aid of pipette. A check count was performed. The number of alive nauplii after 24 h was noted. The mortality, end point of this bioassay was defined as the absence of controlled forward motion of nauplii during 30 s of observation. The controls used were 5% DMSO, saline and podophylotoxin (Huang et al., 2002; Lee et al., 2002; Padmaja et al., 2002; Verdi et al., 2004; Sarker et al., 2012).

Results and Discussion

Solid-phase extraction (SPE) of the MeOH extract of the aerial parts of Pedicularis sibthorpii Boiss., Scrophulariaceae, followed by reversed-phase prep-HPLC analyses of the SPE fractions (10, 20, 40 and 60% aqueous MeOH fractions) afforded three phenylethanoids, verbascoside (1, Nazemiyeh et al., 2008c; Delazar et al., 2005, 2012), martynoside (2, Toth et al., 2007) and isomartynoside (3, Calis et al., 1984), an iridoid, aucubin (4, Bernini et al., 1984; Rønsted et al., 2000), a flavonoid glycoside, luteolin 7-O-β-D-glucopyranoside (5, (Mabry et al., 1970; Suntar et al., 2012), and a monosaccharide mannitol (6, Bock & Pedersen, 1983; SDBS, 2012). All isolated compounds were identified unequivocally by UV and NMR analyses. All spectroscopic data were in agreement with respective published data. While verbascoside (1) was previously reported from P. sibthorpii (Eribekyan et al., 1991), to the best of our knowledge, this is the first report on the occurrence of compounds 2-6 in this species. Within the genus Pedicularis, the distribution of phenylethanoids glycosides, especially verbascoside (1), appears to be widespread (Table 1). Iridoids, e.g., aucubin (4), also occur in many Pedicularis species (Chu et al., 2011).

The free-radical-scavenging activity of the extracts and SPE fractions were determined by the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free-radical-scavenging assay (Kumarasamy et al., 2002, 2007) (Table 2). This assay is based on the ability of DPPH, a stable free-radical, to decolorize in the presence of free-radical-scavengers (antioxidants). The absorption maximum (λ_max in MeOH) of DPPH at 517 nm and its visible deep purple colour are because of its odd electron (Kumarasamy et al., 2007). When DPPH accepts an electron, donated by a free-radical scavenger, DPPH is decolorized, and the extent of decolorization can be quantitatively measured from the changes in absorbance. The MeOH extract showed the highest level of free-radical scavenging activity with a RC50 value of 3.36 ×10^-2 mg/mL among all extracts, whereas the dichloromethane extract did not show any activity at test concentrations. The activity of the MeOH extract was mostly contributed by the SPE fractions of 20, 40 and 60% aq. MeOH fractions (Table 2). Of the six isolated compounds (1-6) from various SPE fractions, four were phenolic compounds (1-3, 5), and are well known for their free-radical scavenging properties (Delazar et al., 2012; Suntar et al., 2012). This is the first report on the free-radical-scavenging property of P. sibthorpii growing in Iran. However, free-radical scavenging or antioxidant property was also documented in several other species of the genus Pedicularis, e.g., P. alaschanica (Wang et al., 1996), P. decora (Gao et al., 2011), P. lasiophrys (Li et al., 1992) P. mexicana (Moreno-Escobar et al., 2011), P. striata (Li et al., 1992, 1997; Mu et al., 2008) and almost in all cases, the activity was found to be associated with phenylpropanoid glycosides, e.g., 1-3 (Li et al., 1992; Miao et al., 2003; Mu et al., 2008; Shi et al., 2011).

In the in vitro antimicrobial assay, only the MeOH extract was found to be active against three bacterial strains, P. aeruginosa, S. aureus and S. epidermidis, but not against the fungal strain C. albicans (Table 3), and the MIC was 200 μg/mL. Similar antimicrobial properties were also previously observed with the MeOH extracts of many other species of the family Scrophulariaceae, e.g., Verbascum vacillance, V. chianophyllum, V. cilicium, V. trapifolium, V. meinkianum, Scrophulariaea tricopoda and Scrophulariaea candelabrum (Dulger, 2006; Dulgar & Hagioglu, 2008). Earlier studies on the antimicrobial activity of the genus Pedicularis revealed that compounds isolated from P. armata were active against S. aureus, and P. olympica was active against Gram-positive strains (S. aureus and M. luteus) (Dulger & Ugurlu, 2005; Yuan et al., 2007). Thus, the findings of the current study are in agreement with previous reports. SPE fractions of the antimicrobial MeOH extract were also tested against susceptible strains (Table 3). Among the SPE fractions, the 40 and 60% SPE fractions were active against P. aeruginosa, S. aureus and S. epidermidis. It is noteworthy, that neither the most polar (10% MeOH-water), nor the least polar (100% MeOH) SPE fractions displayed any activity against any of the above strains. The most prominent antibacterial activity was exhibited by the 60% MeOH-water SPE fraction against S. epidermidis with a zone of inhibition of 24.5 mm.

In the brine shrimp lethality assay (Meyer et al., 1982), none of the extracts or fractions showed any toxicity at the highest test concentration (1 mg/mL) (Table 2).

The phytochemical investigation of the aerial parts of P. sibthorpii has demonstrated that this plant is a good source of phenolic glycosides, and the MeOH extract has significant free-radical scavenging and antibacterial properties, with no general toxicity.

References

Akdemir Z, Calis I, Junior P 1991. Iridoid and phenylpropanoid glycosides from Pedicularis condensate. Phytochemistry 30: 2401-2402.

Aqil F, Ahmad I 2007. Antibacterial properties of traditionally used Indian medicinal plants. Methods Find Exp Clin Pharmacol 29: 79-92.

Asnaashari S, Delazar A, Alipour SS, Nahar L, Williams AS, Pasdaran A, Mojarab, M, Fatih-Azad F, Sarker SD 2010. Chemical composition, free-radical-scavenging and insecticidal activities of the aerial parts of Stachys byzantina. Arch Biol Sci 62: 653-662.

Babaei H, Sadeghpour O, Nahar L, Delazar A, Nazemiyeh H, Mansouri MR, Poursaeid N, Asnaashari S, Moghadam SB, Sarker SD 2008. Antioxidant and vasorelaxant activities of flavonoids from Amygdalus lycioides. Turkish J Biol 32: 203-208.

BaoNing S, Li Y, ZhongJian J 1997. Neolignan, phenylpropanoid and iridoid glycosides from Pedicularis verticillata. Phytochemistry 45: 1271-1273.

Bernini R, Iavarone C, Trogolo C 1984. 1-O-β-D-Glucopyranosyleucommiol, an iridoid glucoside from Aucuba japonica. Phytochemistry 23: 1431-1433.

Bock K, Pedersen C 1983. Carbon-13 nuclear magnetic resonance spectroscopy of monosaccharides. Adv Carbohydr Chem Biochem 41: 27-66.

Bussmann RW, Malca-Garcia G, Glenn A, Sharon D, Chait G, Diaz D, Pourmand K, Jonat B, Somogy S, Guardado G, Aguirre C, Chan R, Meyer K, Kuhlman A, Townesmith A, Effio-Carbajal J, Frias-Fernandez F, Benito M 2010. Minimum inhibitory concentrations of medicinal plants used in Northern Peru as antibacterial remedies. J Ethnopharmacol 132: 101-108.

Calis I, Lahloub MF, Rogenmoser E, Sticher O 1984. Isomartynoside, a phenylpropanoid glycoside from Galeopsis pubescens. Phytochemistry 23: 2313-2315.

Carron R, Montero MK, Martin ML, Moran A, San Roman L 1988. Phenolic compounds of Pedicularis sylvatica. Fitoterapia 6: 511-512.

Chu HB, Zeng GZ, Zhu MJ, He WJ, Zhang YM, Tan NH 2011. Chemical constituents of Pedicularis densispica Franch. Zeitschrift Fur Naturforschung Section B-A J Chem Sci 66: 641-646.

Chu HB, Tan NH, Zhang YM 2007. Chemical constituents from Pedicularis rex CB Clarke. Zeitschrift Fur Naturforschung Section B-A J Chem Sci 62: 1465-1470.

Delazar A, Byres M, Gibbons S, Kumarasamy Y, Modarresi M, Nahar L, Sarker SD 2004. Iridoid glycosides from Eremostachys glabra. J Nat Prod 67: 1584-1587.

Delazar A, Gibbons S, Kumarasamy Y, Nahar L, Shoeb M, Sarker SD 2005. Antioxidant phenylethanoid glycosides from the rhizomes of Eremostachys glabra (Lamiaceaea). Biochem Syst Ecol 33: 87-90.

Delazar A, Biglari F, Esnaashari S, Nazemiyeh H, Talebpour AH, Nahar L, Sarker SD 2006. GC-MS analysis of the essential oils, and the isolation of phenylpropanoid derivatives from the aerial parts of Pimpinella aurea. Phytochemistry 67: 2176-2181.

Delazar A, Naseri M, Nahar L, Moghadam S, Esnaashari S, Nazemiyeh H, Sarker SD 2007. GC-MS analysis and antioxidant activities of essential oils of two cultivated Artemisia species. Chem Nat Compds 43: 112-114.

Delazar A, Nazifi E, Movafeghi A, Nahar L, Nazemiyeh H, Moghadam SB, Asnaashari S, Sarker SD 2009. GC-MS analyses of Ornithogalum procerum. DARU 17: 33-36.

Delazar A, Khodaie L, Afsar J, Nahar L, Sarker SD 2010a. Isolation and free-radical-scavenging properties of cyanidin 3-O-glycosides from the fruits of Ribes biebersteinii Berl. Acta Pharmaceutica 60: 1-11.

Delazar A, Nazifi E, Movafeghi A, Nazemiyeh H, Hemmati S, Nahar L, Sarker SD 2010b. Analyses of phytosterols and free radical scavengers from the bulbs of Ornithogalum cuspidatum Bertol. BLACPMA 9: 87-92.

Delazar A, Delnavazi MR, Nahar L, Moghadam SB, Mojarab M, Gupta A, Williamns A, Rahman MM, Sarker SD 2011a. Lavandulifolioside B: a new phenylethanoid glycoside from the aerial parts of Stachys lavandulifolia Vahl. Nat Prod Res 25: 8-16.

Delazar A, Bahmani M, Hekmat-Shoar H, Tabatabaei-Raisi A, Asnaashari S, Nahar L, Sarker SD 2011b. Effect of altitude, temperature and soil on essential oil production in Thymus fedtschenkoi flowers in Osko and surrounding areas in Iran. J Essential Oil Bearing Plants 4: 23-29.

Delazar A, Delnavazi M-R, Yassa N, Parkhideh S, Delazar N, Nahar L, Sarker SD 2012. Essential oil composition and isolation of free-radical-scavenging phenolic glycosides from the aerial parts of Ajuga chamaepitys (L.) Schreb. (Lamiaceae) growing in Iran. Rev Bras Farmacog 22: 299-305.

Di DL, Chen J, Shi YP 2004. Determination of phenylpropanoid glycosides in Chinese herbal extracts from Pediculatis species by HPLC. J Liq Chromatog Rel Technol 27: 2235-2245.

Dulgar B, Hagioglu N 2008. Evaluation of antimicrobial activity of two endemic Scrophulariaceae members. Asian J Chem 20: 6385-6390.

Dulger B 2006. Antimicrobial activity of some endemic Scrophulariaceae from Turkey. Pharm Biol 44: 672-676.

Dulger B, Ugurlu E 2005. Evaluation of antimicrobial activity of some endemic Scrophulariaceae members from Turkey. Pharm Biol 43: 275-279.

Eribekyan MI, Agababyan EY, Arutyunyan LS, Mnatsakanyan VA 1991. Phenylpropanoid glycosides of Pedicularis condensate, P. wilhelmslana and P. sibthorpii. Khimiya Prirodnykh Soedinenii 723-724.

Essawi T, Srour M 2000. Screening of some Palestinian medicinal plants for antibacterial activity. J Ethnopharmacol 70: 343-349.

Fujii M, Miyaichi Y, Tomimori T 1995. Flavonoid, phenylethanoid and iridoid constituents of the whole plant of Pedicularis longiflora var. tubiformis. Planta Med 61: 584-584.

Gao JJ, Jia ZJ 1995. Lignan, iridoid and phenylpropanoid glycosides from Pedicularis alaschanica. Ind J Chem Sect B-Org Chem Including Med Chem 34: 466-468.

Gao JJ, Yang L, Jia ZJ 1997. A new eremophilane sesquiterpenoid and a new iridoid from Pedicularis striata subsp. Arachnoids. Planta Medica 63: 248-260.

Gao ML, Li YF, Yang JX 2011. Protective effect of Pedicularis decora Franch root extracts on oxidative stress and hepatic injury in alloxan-induced diabetic rats. J Med Plant Res 5: 5848-5856.

Huang JM, Nakade K, Kondo M, Yang CS, Fukuyama Y 2002. Brine shrimp lethality test active constituents and new highly oxygenated seco-prezizaane-type sesquiterpenes from Illicium merrillianum. Chem Pharm Bull (Tokyo) 50: 133-136.

Jia ZJ, Gao JJ, Liu ZM 1994. Iridoid and phenylpropanoid glycosides from Pedicularis plicata Maxim. Ind J Chem Sect B-Org Chem Including Med Chem 33: 460-464.

Jia ZJ, Gao JJ 1993. Phenylpropanoid glycosides from Pedicularis struata Pall ssp. arachnoidea. Phytochemistry 34: 1188-1190.

Jia ZJ, Liu ZM, Wang CZ 1992. Phenylpropanoid and iridoid glycosides from Pedicularis lasiophrys. Phytochemistry 31: 263-266.

Jia ZJ, Liu ZM, Wang CZ 1991. Phenylpropanoid and iridoid glycosides from Pedicularis spicata. Phytochemistry 30: 3745-3747.

Jiang TF, Ou QY, Shi, YP 2003. Separation and determination of phenylpropanoid glycosides from Pedicularis species by capillary electrophoresis. J Chromatogr A, 986: 163-167.

Khodaei L, Delazar A, Nazemiyeh H, Asnaashari S, Nahar L, Sarker SD 2012. Composition of the volatile oils of the aerial parts of Pedicularis sibthorpii and P. wilhelmsiana growing in Iran. J Essen Oil Bearing Plants (in press).

Kumarasamy Y, Fergusson M, Nahar L, Sarker SD 2002. Biological activity of moschamindole from Centaurea moschata. Pharm Biol 40: 307-310.

Kumarasamy Y, Byres M, Cox PJ, Jaspars M, Nahar L, Sarker SD 2007. Screening seeds of some Scottish plants for free-radical scavenging activity. Phytother Res 21: 615-21.

Lee S, Min B, Kho Y 2002. Brine shrimp lethality of the compounds from Phryma leptostachya L. Arch Pharm Res 25: 652-654.

Li J, Ge RC, Zheng RL, Liu ZM Jia ZJ 1997. Antioxidative and chelating activities of phenylpropanoid glycosides from Pedicularis striata. Acta Pharmacol Sin 18: 77-80.

Li J, Zheng RL, Liu ZM, Jia ZJ 1992. Scavenging effects of phenylpropanoid glycosides on superoxide and its antioxidation effect. Acta Pharmacol Sin 13: 427-430.

Mabry TJ, Markham KR, Thomas MB 1970. The Systematic Identification of Flavonoids, Springer-Verlag, New York.

Maia JGS, Zoghbi MGB, Andrade EHA, Da Silva MHL 2000. Essential oil from Conobea scoparioides (Cham.and Schltdl.) Benth. Flav Fragrance J 15: 413-414.

Meyer BN, Ferringi RN, Putnam JE, Jacobson LB, Nichols DE, McLaughlin JL 1982. Brine shrimp: a convenient bioassay for active plant constituents. Planta Med 45: 31-34.

Miao JL, Wang WF, Yao S, Navaratnam S, Parsons BJ 2003. Antioxidative properties of martynoside: Pulse radiolysis and laser photolysis study. Free Rad Res 37: 829-833.

Modaressi M, Delazar A, Nazemiyeh H, Fathu-Azad E, Smith E, Rahman MM, Gibbons S, Nahar L, Sarker SD 2009. Antibacterial iridoid glucosides from Eremostachys laciniata. Phytother Res 23: 99-103.

Moreno-Escobar JA Bazaldua S, Villarreal ML, Bonilla-Barbosa JR, Mendoza S, Rodriguez-Lopez V 2011. Cytotoxic and antioxidant activities of selected Lamiales species from Mexico. Pharm Biol 49: 1243-1248.

Mu P, Gao X, Jia ZJ, Zheng RL 2008. Natural antioxidant pedicularioside G inhibits angiogenesis and tumourigenesis in vitro and in vivo. Basic Clin Pharmacol Toxicol 102: 30-34.

Nazemiyeh H, Delazar A, Ghahramani M-A, Talebpour A-H, Nahar L, Sarker SD 2008a. Phenolic glycosides from Phlomis lanceolata (Lamiaceae). Nat Prod Commun 3: 53-56.

Nazemiyeh H, Bahadori F, Delazar A, Ay M., Topcu G, Kolak U, Nahar L, Majinda RRT, Sarker SD 2008b. Antioxidant phenolic compounds from the leaves of Erica arborea (Ericaceae). Nat Prod Res 22: 1385-1392.

Nazemiyeh H, Rahman MM, Gibbons S, Nahar L, Delazar A, Ghahramani M-A, Talebpour A-H, Sarker SD 2008c. Assessment of the antibacterial activity of phenylethanoid glycosides from Phlomis lanceolata against multiple-drug-resistant strains of Staphylococcus aureus. J Nat Med 62: 91-92.

Nazemiyeh H, Latifpoor F, Delazar A, Razavi SM, Esna-Ashari S, Kasebi N, Talebpour A-H, Nahar L, Sarker SD 2011. Chemical composition, free-radical-scavenging and antibacterial properties of the essential oil of a citronellol producing new chemotype of Thymus pubescens Boiss. & Kotschy ex Celak. Records of Nat Prod 5: 184-192.

Nazifi E, Delazar A, Movafeghi A, Nazemiyeh H, Nahar L, Sarker SD 2008. GC-MS analysis of the dichloromethane extract of the bulbs of Ornithogalum cuspidatum Bert. (Family: Liliaceae) from Iran. Records of Nat Prods 2: 94-99.

Padmaja R, Arun PC, Prashanth D, Deepak M, Amit A, Anjana M 2002. Brine shrimp lethality bioassay of selected Indian medicinal plants. Fitoterapia 73: 508-510.

Pasdaran A, Delazar A, Nazemiyeh H, Nahar L, Sarker SD 2012. Chemical composition, and antibacterial (against Staphylococcus aureus) and free-radical-scavenging activities of the essential oils of Scrophularia amplexicaulis Benth. Rec Nat Prod (in press).

Perumal S, Ignacimuthu RS, Sen A 1998. Screening of 34 Indian medicinal plants for antibacterial properties. J Ethnopharmacol 62: 173-182.

Razavi SM, Nazemiyeh H, Hajiboland R, Kumarasamy Y, Delazar A, Nahar L, Sarker SD 2008. Coumarins from the aerial parts of Prangos uloptera (Apiaceae). Rev Bras Farmacogn 18: 1-5.

Razavi SM, Nazemiyeh H, Delazar A, Asnaashari S, Hajiboland R, Sarker SD, Omidi Y 2011. Chemical variation of the essential oil of Prangos uloptera DC. at different stages of growth. Nat Prod Res 25: 663-668.

Rønsted N, Gobel E, Franzyk H, Jensen SR, Olsen CE 2000. Chemotaxonomy of Plantago. iridoid glucosides and caffeoyl phenylethanoids glycosides. Phytochemistry 55: 337-348.

Sarker SD, Nahar L, Gujja S, Begum, Celik S 2012. Bioactivity of Centaurea persica Boiss. (Asteraceae). Arch Biol Sci 64: 517-523.

Schneider MJ, Romero KA 1995. Iridoid glycosides from Pedicularis punctata. Abstracts of Papers American Chemical Society 210: ORGN 355.

SDBS 2012. Spectral Database for Organic Compounds, National Institute of Advanced Industrial Science and Technology (AIST). URL: http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi.

Shi Y, Lin W, Fan P, Zhongjian J, Yao S, Jiohong K, Wang W, Zheng R 1999. Fast repair of hydroxyl radical purine deoxynocleotide adducts by phenylpropanoid glycosides and their derivatives from Chinese herbs. Biochim Biophys Acta (BBA)-General Subjects 1-2: 1472.

Shi YM, Yao SD, Jia ZJ, Lin NY, Zheng RL 2011. Dietary phytophenols act as scavengers of reducing radicals. Food Chem 124: 1322-1327.

Suntar I, Akkol K, Keles H, Yesilada E, Sarker SD, Arroo R, Baykal T 2012. Efficacy of Daphne oleoides subsp. kurdica used for wound healing: identification of active compounds through bioassay guided isolation technique. J Ethnopharmacol 141: 1058-1070.

Toth E, Toth G, Mathe I, Blunden G 2007. Martynoside, forsythoside B, lananein and 7a-acetoxyroyleanone from Ballota nigra L., Biochem Syst Ecol 35: 894-897.

Verdi LG, Pizzolatti MG, Montanher ABP, Brighente IMC, Smania A, Smania EDA, Simionatto EL, Delle Monache F 2004. Antibacterial and brine shrimp lethality tests of biflavonoids and derivatives of Rheedia gardnerian. Fitoterapia 75: 360-363.

Wang CZ, Jia ZJ 1997. Lignan, phenylpropanoid and iridoid glycosides from Pedicularis torta. Phytochemistry 45: 159-166.

Wang CZ, Jia ZJ, Shen XM 1997. Phenylpropanoid, neolignan and iridoid glycosides from Pedicularis semitorta. Ind J Chem Sect B-Org Chem Including Med Chem 36: 160-153.

Wang PF, Kang JH, Zheng RL, Yang ZH, Lu JF, Gao JJ, Jia ZJ 1996. Scavenging effects of phenylpropanoid glycosides from Pedicularis on superoxide anion and hydroxyl radical by the spin trapping method. Biochem Pharmacol 51: 687-691.

Yang L, Wang CZ, Jia ZJ 1995. Iridoids in roots of Pedicularis chinensis. Phytochemistry 40: 491-494.

Yuan CS, Sun XB, Zhao PH, Cao MA 2007. Antibacterial constituents from Pedicularis armata. J Asian Nat Prod Res 9: 673-677.

Zhang ZX, Xie WD, Jia ZJ 2008. Glycosides from two Pedicularis species. Biochem Syst Ecol 36: 467-472.

Zhang B-B, Shi K, Liao Z-X, Dai Y, Zou Z-H. 2011. Phenylpropanoid glycosides and triterpenoid of Pedicularis kansuensis Maxim. Fitoterapia 82: 854-860.

Zhu M, Tan N, Zhu H, Zeng G, He W, Yu B, Chen X 2010. Anti-sports anaemia effects of verbascoside and martynoside in mice. Int J Sport Med 31: 537-541.

Received 8 Jun 2012

Accepted 20 Aug 2012

Publication Dates

• Publication in this collection
  18 Sept 2012
• Date of issue
  Dec 2012

History

• Received
  08 June 2012
• Accepted
  20 Aug 2012