Isolation of Flavonoids and Flavonoid Glycosides from Myrsine africana and Their Inhibitory Activities against Mushroom Tyrosinase

Abstract

Bioassay-guided fractionation of the methanol extract of the shoots of Myrsine africana led to the isolation of the new compound myricetin 3-O-(2″,4″-di-O-acetyl)-α-l-rhamnopyranoside (9) and 11 known compounds. The known compounds quercetin 3-O-(3″,4″-di-O-acetyl)-α-l-rhamnopyranoside (8), rutin (10), quercetin 3-O-α-l-rhamnopyranoside (11), and myricetin 3-O-α-l-rhamnopyranoside (12) are reported for the first time from the methanol extract of the shoots of M. africana. Compounds 10 and 12 showed significant inhibition of tyrosinase with 50% inhibition (IC values) of the enzyme at 0.13 ± 0.003 and 0.12 ± 0.002 mM, respectively, which was supported by the docking fitness scores obtained through molecular docking analysis. In addition, compounds 1-12 displayed significant antioxidant activity with IC values ranging 1.90 to 3.90 μM.

Natural and Bioinspired Phenolic Compounds as Tyrosinase Inhibitors for the Treatment of Skin Hyperpigmentation: Recent Advances

“…Low IC50 values against both monophenolase and diphenolase activty of mushroom tyrosinase have been very recently reported for p-coumaric and caffeic acid [66], belonging to the cinammic acid family ( Figure 7). The IC50 values together with structural formulas for other phenolic compounds widely distributed in nature that have been the subject of studies that appeared in the last five years [53,62,63,[67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82] Low IC 50 values against both monophenolase and diphenolase activty of mushroom tyrosinase have been very recently reported for p-coumaric and caffeic acid [66], belonging to the cinammic acid family ( Figure 7). Moving to simple phenols, significant inhibition activity has been described for 4-hydroxybenzyl alcohol (IC50 = 6 μM) [61] and isoeugenol (IC50 = 33.3 μM) [62], which would appear more efficient than resorcinol [55] or rhododendrol [63] themselves.…”

“…Low IC50 values against both monophenolase and diphenolase activty of mushroom tyrosinase have been very recently reported for p-coumaric and caffeic acid [66], belonging to the cinammic acid family (Figure 7). The IC50 values together with structural formulas for other phenolic compounds widely distributed in nature that have been the subject of studies that appeared in the last five years [53,62,63,[67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82] The IC 50 values together with structural formulas for other phenolic compounds widely distributed in nature that have been the subject of studies that appeared in the last five years [53,62,63,[67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82] are also reported in Figures 4-8.…”

In Vitro Antioxidant, Anti-Inflammatory and Skin Permeation of Myrsine africana and Its Isolated Compound Myrsinoside B

“…Previous studies have identified and characterised myrsinoside B (94.39% purity) amongst other compounds (Kishore et al, 2018). Lall et al (2017) reported noteworthy elastase inhibition for M. africana (28.04 µg/ml) and myrsinoside B (4.69 µg/ml).…”

“…It is also used in various culinary applications as a fragrance, flavoring agent, spice, and appetizer (Ahmad et al, 2011b).Additional uses include as an anthelmintic, antibacterial, for the treatment of boils, and scanty urine (Watt and Breyer-Brandwijk, 1962;Killick, 1969;Githiori et al, 2002;Abbasi et al, 2010). The reported use of M. africana as a blood purifier spurs interest around its potential application as an anti-wrinkle agent as such agents often play an important role in maintaining healthy skin (Kishore et al, 2018).…”

“…Further, this study aimed to characterize and identify a means of delivery of myrsinoside B into the skin. The extract and isolated myrsinoside B samples used in this study were the same as that produced in previous studies (Lall et al, 2017;Kishore et al, 2018).…”