Fatty acid acylated flavonol glycosides from the seeds of Nephelium lappaceum and their nitric oxide suppression activity

Siamfuranones A-C, three novel furanone derivatives from the flowers of Uvaria siamensis and their biological activities

Three previously undescribed furanone derivatives named siamfuranones A-C (1-3), together with 11 known compounds (4-14), were isolated from the flowers of Uvaria siamensis. Their planar structures were determined through analysis of spectrometric and spectroscopic evidence, while electronic circular dichroism (ECD) calculations were used to determine their absolute configurations. In addition, gauge-including atomic orbitals (GIAO) NMR chemical shift calculation, supported by the advanced statistical method DP4 plus, was used to confirm the relative configuration of siamfuranone B (2). All the isolated compounds were evaluated against two cancer cell lines (A549 and Hela), and screened for antibacterial activities. Furthermore, they were assessed for cytotoxicity against a normal cell line (Vero cell).

Synergistic impact of arbutin and kaempferol-7-O-α-L-rhamnopyranoside from Nephelium lappaceum L. on whitening efficacy and stability of cosmetic formulations

Four flavonoid glycosides, namely quercetin-3-O-rhamnoside (1), kaempferol-3-O-β-D-glucopyranosyl (2), kaempferol-7-O-α-L-rhamnopyranoside (3), and kaempferol-3-O-β-D-glucopyranosyl-7-O-α-L-rhamnopyranoside (4), from Nephelium lappaceum L. seeds were evaluated for their efficacy against melanin inhibition in B16F10 melanoma cells and tyrosinase inhibition. Among them, kaempferol-7-O-α-L-rhamnopyranoside (3) displayed the highest potency in both activities without any significant cytotoxicity. The combination of compound 3 and arbutin in specific proportions demonstrated a synergistic effect (CI < 1) in inhibiting melanin production in B16F10 cells and tyrosinase inhibition. Additionally, a cosmetic formulation containing compound 3 and arbutin as active ingredients exhibited favorable stability under accelerated storage conditions. Quantitative analysis indicated that compound 3 and arbutin levels in the formulation were above 90% after one month of storage. Determination of the formulation's shelf life using the Q10 method, estimating it to be around 5.2 months from the date of manufacture. The synergy between arbutin and kaempferol-7-O-α-L-rhamnopyranoside (3) extracted from N. lappaceum substantially enhances both the whitening effectiveness and the stability of cosmetic formulations.