Plants of the family Lamiaceae as a source of therapeutic agents against <i>Acanthamoeba</i> infections

Mrva, Martin; Malíková, Lucia; Garajová, Mária

doi:10.1590/0074-02760240171

Abstract

BACKGROUND Acanthamoebae are causative agents of severe and complicated human infections without a standard effective therapy to date. Therefore, the research is focused on the development of new amoebicidal drugs based on the natural products. Plants of the family Lamiaceae are typical with several phenolic secondary metabolites that make them interesting in medical point of view.

OBJECTIVE In this review, we concentrate on anti-Acanthamoeba activities of plant extracts, essential oils, and phytochemicals of Lamiaceae in the published literature.

FINDINGS A total of 13 articles in the research field were found. Totally, 16 plant species belonging to family Lamiaceae were studied against trophozoites and cysts of Acanthamoeba in in vitro conditions. Low toxicity of the Lamiaceae plant extracts to tissue cultures enhances their possible potential for clinical use. The research demonstrated promising trophocidal and cysticidal effects against acanthamoebae. Further research is needed with inclusion of more clinical isolates and in vivo studies.

MAIN CONCLUSION Reviewing the related literature highlights the promising amoebicidal activities of plant extracts, essential oils and bioactive compounds of family Lamiaceae. Identifying the active components could lead to production new effective and well-tolerated drugs for the Acanthamoeba infections treatment.

Key words:
Acanthamoeba ; Lamiaceae; plant extracts; essential oils; amoebicidal effect

[TFN1] ^*Asterisk marks the strain previously published as Neffʼs strain of Acanthamoeba castellanii which was transferred recently to the species Acanthamoeba terricola by Corsaro et al.⁵⁹

Plant species	Extract	Amoeba strain	Strain source	Amoebicidal activity	Reference
Melissa officinalis	Methanol	A. castellanii	clinical	72 h - at 32 mg/mL 44.3% of trophozoites and 30.0% of the cysts killed	⁴¹
Origanum laevigatum	Methanol	A. castellanii	clinical	72 h - at 16 mg/mL no viable trophozoites 72 h - at 32 mg/mL 47.7% of the cysts killed	⁴⁹
Origanum syriacum	Methanol	A. castellanii	clinical	6 h - at 16 mg/mL no viable trophozoites 24 h - at 32 mg/mL no viable cysts	⁴⁹
Salvia caespitosa	Methanol	A. castellanii 1BU	clinical	72 h - at 8 mg/mL no viable trophozoites, at 16 mg/mL no viable cysts	⁴³
Salvia staminea	Methanol	A. castellanii 1BU	clinical	72 h - at 1 mg/mL no viable trophozoites, at 8 mg/mL no viable cysts	⁴³
Satureja cuneifolia	Methanol	A. castellanii	clinical	24 h - 16 mg/mL no viable trophozoites 72 h - at 32 mg/mL 46.3% of the cysts killed	⁴¹
Scutellaria baicalensis	Aqueous	A. royreba A. castellanii A. polyphaga	Not stated	50 mg/mL - strong trophocidal effect against A. royreba, less effective against A. castellanii and A. polyphaga	⁵⁵
Teucrium chamaedrys	Methanol	A. castellanii	clinical	48 h - at 16 mg/mL no viable trophozoites 72 h - at 32 mg/mL 30.3% of the cysts killed	⁵⁰
Teucrium polium	Methanol	A. castellanii	clinical	48 h - at 32 mg/mL no viable trophozoites 72 h - at 32 mg/mL 19.3% of the cysts killed	⁵⁰
Teucrium ramosissimum	Hexane, ethyl acetate, acetone, ethanol	A. terricola Neff^*	environmental	72 h - 144 h IC₅₀ against trophozoites > 100 µg/mL	⁵¹
Thymus capitatus	Ethanol-aqueous	A. terricola Neff^*	environmental	96 h - IC₅₀ against trophozoites 21.51 µg/mL	⁴⁷
Thymus sipyleus	Methanol	A. castellanii 1BU	clinical	72 h - at 1 mg/mL no viable trophozoites, at 4 mg/mL no viable cysts	⁴⁶

Plant species	Most important compounds	Amoeba strain	Strain source	Amoebicidal activity	Reference
Melissa officinalis	Not stated	A. castellanii	clinical	24 h - at 0.625 µg/mL no viable trophozoites 48 h - at 40 µg/mL no viable cysts	⁵²
Mentha piperita	Not stated	Acanthamoeba sp.	Not stated	24 h - at 30% concentration no viable trophozoites	⁵³
Mentha piperita	Not stated	A. castellanii	clinical	24 h - at 2.5 µg/mL no viable trophozoites 72 h - at 40 µg/mL no viable cysts	⁵²
Ocimum basilicum	Not stated	A. castellanii	clinical	24 h - at 5 µg/mL no viable trophozoites 72 h - at 40 µg/mL 63.3% of the cysts killed	⁵²
Rosmarinus officinalis	1.8-cineole 25.23%, α-pinene 18.81%, camphor 15.26%, camphene 10.82%, borneol 2.87%, caryophyllene 1.91%	A. polyphaga ApUP	clinical	144 h - at 100 µg/mL 50% inhibition of trophozoites	⁵⁴
Salvia sclarea	ferruginol, salvipisone, aethiopinone, 1-oxo-aethiopinone	A. castellanii 309	environmental	72 h - at 0.1 mg/mL reduction of trophozoites: 71.9% by ferruginol, 38.8% by salvipisone, 56.3% by aethiopinone, 55,3% by 1-oxo-aethiopinone	⁴⁴
Scutellaria baicalensis	baicalin, baicalein, wogonoside, oroxylin A	A. castellanii ATCC 30234, A. polyphaga ATCC 30461	Clinical + isolated from yeast culture	4 h Oroxylin A and wogonoside - 0.4 and 0.5 log reduction in trophozoites viability, respectively. 4 h Combination of baicalein and oroxylin A - 0.50-0.65 log reduction in trophozoites viability.	⁵⁶
Teucrium ramosissimum	δ-cadinol 18.70%, δ-cadinene 18.63%, β-eudesmol 12.13%	A. terricola Neff^*	environmental	72 h - IC₅₀ against trophozoites 25.73 µg/mL	⁵¹
Thymus capitatus	carvacrol 81.53%, p-cymene 6.10%, γ-terpinene 2.64%, caryophyllene 2.66%	A. terricola Neff^*	environmental	96 h - IC₅₀ against trophozoites 2.73 µg/mL	⁴⁷

Plants of the family Lamiaceae as a source of therapeutic agents against Acanthamoeba infections

Abstract