The effect of isolates from Cassipourea flanaganii (Schinz) alston, a plant used as a skin lightning agent, on melanin production and tyrosinase inhibition.

Autor: Langat MK; Jodrell Laboratory, Natural Capital and Plant Health Department, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, United Kingdom; Natural Products Research Group, Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, United Kingdom; School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4041, South Africa. Electronic address: m.langat@kew.org., Dlova NC; Department of Dermatology, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Private Bag X 7, Congella, 4013, Durban, South Africa., Mulcahy-Ryan LE; School of Life Sciences, Pharmacy and Chemistry, Kingston University, London, Kingston, KT1 2EE, United Kingdom., Schwikkard SL; School of Life Sciences, Pharmacy and Chemistry, Kingston University, London, Kingston, KT1 2EE, United Kingdom., Opara EI; School of Life Sciences, Pharmacy and Chemistry, Kingston University, London, Kingston, KT1 2EE, United Kingdom., Crouch NR; School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4041, South Africa; Biodiversity Research, Monitoring and Assessment, South African National Biodiversity Institute, PO Box 52099, Berea Road, 4007, Durban, South Africa., Hiles JD; Natural Products Research Group, Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, United Kingdom; School of Life Sciences, Pharmacy and Chemistry, Kingston University, London, Kingston, KT1 2EE, United Kingdom., Mulholland DA; Natural Products Research Group, Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, United Kingdom; School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4041, South Africa.
Jazyk: angličtina
Zdroj: Journal of ethnopharmacology [J Ethnopharmacol] 2021 Jan 10; Vol. 264, pp. 113272. Date of Electronic Publication: 2020 Aug 15.
DOI: 10.1016/j.jep.2020.113272
Abstrakt: Ethnopharmacological Relevance: The Zulu and Xhosa people of South Africa use the stem bark of Cassipourea flanaganii as a skin-lightning cosmetic.
Aim of the Study: To isolate and identify compounds responsible for the skin lightning properties from the stem bark of Cassipourea flanaganii and to evaluate their cytotoxicity towards skin cells.
Materials and Methods: Extracts from the stem bark of Cassipourea flanaganii were isolated using chromatographic methods and structures were determined using NMR, IR and MS analysis. The tyrosinase inhibitory activity and the ability to inhibit the production of melanin were determined using human primary epidermal melanocyte cells. Cytoxicity was established using the same melanocytes and a neutral red assay.
Results: One previously undescribed compound, ent-atis-16-en-19-al (1) along with the known ent-atis-16-en-19-oic acid (2), ent-atis-16-en-19-ol (3), ent-kaur-16-en-19-oic acid (4), ent-kaur-16-en-19-al (5), ent-manoyl oxide (6), guinesine A (7), guinesine B (8), guinesine C (9), lichenxanthone (10), 2,4-dihydroxy-3,6-dimethyl benzoic acid methyl ester (11), lynoside (12), lupeol (13), β-amyrin (14), docosyl ferulate (15), stigmasterol, sitosterol and sitosterol-O-glucoside were isolated in this investigation. An impure fraction containing compound 3 was acetylated to obtain 19-acetoxy-ent-atis-16-ene (3a). Compounds 10 and 11 are usually isolated from lichen, hence they are possible contaminants of lichen harvested with the bark. Compounds 1, 3a, 5-14 were not significantly cytotoxic to the primary epidermal melanocyte cells (P > 0.05) when compared to the negative and positive controls (DMSO, 0.1% and hydrogen peroxide, 30 wt% in water). Inhibition of tyrosinase was significantly greater with respect to the negative control (P < 0.001) for compounds 3a, 5-8 and 9-10 at 10 μM and for compounds 5-8 and 9-10 at 100 μM. Compared to hydroquinone (the positive control) at 10 μM, the level of inhibition was comparable or to that of compounds 3a, 5, 6, and 8-10 at 10 μM, with 9 and 10 showing a greater level of inhibition. Inhibition of melanin was both concentration and time dependent for all compounds tested with higher melanin content at 24 h compared to 48 h s and at 10 mM compared to100 mM at both time points; melanin content was significantly lower for hydroquinone at both time points and concentrations.
Conclusions: Compounds 1, 5-14, isolated from Cassipourea flanaganii and the derivative 3a showed low cytotoxicity. All compounds had a clear time and concentration dependent effect on melanin content which did not appear to be dependent on their inhibition of tyrosinase.
(Copyright © 2020 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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