Chemical Constituents from Memecylon Scutellatum with Nitric Oxide Inhibitory Activity.

Objectives: Memecylon scutellatum (Lour.) Hook. & Arn. (Melastomataceae) is a relatively lesser-known species within this genus. This study aims to explore its chemical structure profile and evaluate its ability to inhibit NO production. Methods: The chemical structures of MS were elucidated by comparing their NMR data, and all compounds were evaluated for NO inhibition using the Griess assay. Results: One new compound namely, memeloside (1) and fourteen known compounds, 1- O -(β -D-glucopyranosyl)-2-[2-methoxy-4-(ω -hydroxypropyl)-phenoxy]-propan-3-ol (2), (2 R)- O -[4′-(3″-hydroxypropyl)-2′,6′dimethoxyphenyl]-3- O - β -D-glucopyranosyl- sn -glycerol (3), schizandriside (4), 2-butanone 4-glucopyranoside 6′- O -gallate (5), epicatechin (6), epigallocatechin (7), epigallocatechin gallate (8), myricitrin (9), benzyl O - α -L-rhamnopyranosyl-(1→6)- β -D-glucopyranoside (10), benzyl glucopyranoside (11), 3,4,5-trimethoxyphenyl- β -D-glucopyranoside (12), icariside B1 (13), gallic acid (14), and (7 R,8 R)- threo -7,9,9ʹ-trihydroxy-3,3ʹ-dimethoxy-8- O -4ʹ-neolignan 4- O - β -D-glucopyranoside (15) were isolated from the leaves of M. scutellatum. Compounds 4 and 5 significantly exhibited inhibition of NO production, with IC₅₀ values of 88.92 ± 1.42 µM and 17.14 ± 0.98 µM, respectively. Conclusions: One new compound, named memeloside (1) and fourteen known compounds isolated from the leaves of M. scutellatum. Compounds 4 and 5 demonstrated significant inhibition of NO production, with IC₅₀ values of 88.92 ± 1.42 µM and 17.14 ± 0.98 µM, respectively. These results suggested compound 5 could be a promising candidate for further anti-inflammatory research. [ABSTRACT FROM AUTHOR]