Antityrosinase and Antioxidant Effects of ent-Kaurane Diterpenes from Leaves of Broussonetia papyrifera

Abstract

Three new ent-kaurane type diterpenes, broussonetones A-C (1-3), were isolated from leaves of Broussonetia papyrifera, together with seven known compounds, and their structures determined by 1D and 2D NMR and MS methods. Compounds 1-3 were marginal inhibitors of tyrosinase. Antioxidant assays showed them also to be inhibitors of xanthine oxidase. The mild inhibition of tyrosinase and significant inhibition of xanthine oxidase suggests that 1-3 could be useful ingredients in the development of skin-protecting cosmetics.

Cholinesterase and BACE1 inhibitory diterpenoids from Aralia cordata

“…However, all tested diterpenes revealed no scavenging effects of ONOO − and NO· at the concentration of 100 µM. Although there has been much research on cholinesterase inhibition (Thirugnanasampandan et al, 2008;Erta et al, 2009) and antioxidant (Ko et al, 2008) effects of ent-kaurane-type diterpenes, those of A. cordata diterpenes have been established for the first time. To the best of the authors' knowledge, this is the first report of ent-pimarane-type diterpenes demonstrating substantial inhibition of BChE.…”

De Novo Assembly of Expressed Transcripts and Global Transcriptomic Analysis from Seedlings of the Paper Mulberry (Broussonetia kazinoki x Broussonetia papyifera)

“…Recent studies indicate that prenylated flavonols isolated from paper mulberry also have highly effective inhibition of alpha-glucosidase activity [45]. The flavenoid broussochalcone A is the principal inhibitor of cholinesterase [46], tyrosinase and xanthine oxidase [47] and also exhibits potent anti-tumor activity [48]. Therefore, identification of these genes has important implications in the eventual better understanding of the biosynthesis of flavonoids, which may be potent components of drug treatments of human conditions.…”

A Novel MonoterpeneStilbene Adduct with a 4,4‐Dimethyl‐2,3‐diphenylchromane Skeleton from Artocarpus xanthocarpus

“…Inhibitory percentage of each test compound and positive control was determined by the optical density measured at 490 nm after 30 and 60 min of incubation as described in [24] [25].…”

“…The assay was initiated by the addition of xanthine oxidase (0.5 U; 55 ml) to the 96-well plate containing 0.1 mm xanthine (15 ml), 0.1 mm EDTA (14 ml), 25 mm NBT (nitroblue tetrazolium chloride; 16 ml), and various concentrations of 1 or vitamin C, diluted with buffer to 200 ml before incubation at 258 for 30 and 60 min. The superoxide free radical-scavenging activity of each compound was determined by the absorbance measured at 540 nm due to the inhibition of blue formazan formation by the reaction of NBT with the free radicals [24] [25].…”

“…Tyrosinase-inhibition and antioxidant-capacity assays are usual methods used in the preliminary evaluation of new cosmeceuticals. To explore the potential of 1 in cosmeceutical development, these assays were performed as described previously [24] [25]. Although artoxanthochromane (1) exhibits free radical-scavenging and tyrosinase-inhibitory activities, the IC 50 values were not superior to those of both the positive controls, arbutin and ascorbic acid ( Table 2).…”