tailieunhanh - Some compounds isolated from leaves of Lumnitzera racemosa growing in Vietnam

From L. racemosa leaves eight compounds were isolated: myricetin (1), quercetin (2), myricetin 3-O-α-L-rhamnopyranoside (3), myricetin 3-O-(2 -O-galloyl-α-Lrhamnopyranoside) (4), myricetin 3-O-(3 -Ogalloyl-α-L-rhamnopyranoside) (5), 3-Omethylellagic acid (6), (3S,5R,6S,7E)-3,5,6- trihydroxy-7-megastigmen-9-one (7) and gallic acid (8). Their chemical structures were unambiguously elucidated by analysis of 1D and 2D NMR and high resolution ESI mass spectroscopic data, as well as by comparison with those reported in the literature. The α- glucosidase inhibition was evaluated on isolated compounds. Among them, 1, 4, 5, 6 and 8 exhibited good activities with the IC50 values in the range of M. | Science & Technology Development, Vol 20, Some compounds isolated from leaves of Lumnitzera racemosa growing in Vietnam • • • • • Nguyen Hoai Phuong Nguyen Thi Le Thuy Nguyen Trung Duc Nguyen Thi Thanh Mai Nguyen Kim Phi Phung University of Science, VNU-HCM (Received on 16th November 2016, accepted on 30th October 2017) ABSTRACT From L. racemosa leaves eight compounds unambiguously elucidated by analysis of 1D and were isolated: myricetin (1), quercetin (2), 2D NMR and high resolution ESI mass myricetin 3-O-α-L-rhamnopyranoside (3), spectroscopic data, as well as by comparison myricetin 3-O-(2 -O-galloyl-α-Lwith those reported in the literature. The αrhamnopyranoside) (4), myricetin 3-O-(3 -Oglucosidase inhibition was evaluated on isolated galloyl-α-L-rhamnopyranoside) (5), 3-Ocompounds. Among them, 1, 4, 5, 6 and 8 methylellagic acid (6), (3S,5R,6S,7E)-3,5,6exhibited good activities with the IC50 values in trihydroxy-7-megastigmen-9-one (7) and gallic the range of M. acid (8). Their chemical structures were Key words: Lumnitzera racemosa Willd., Lumnitzera, Flavonoid, Megastigmane sesquiterpene INTRODUCTION Lumnitzera racemosa, an Indo-West Pacific mangrove plant, wildly grows in many mangrove forests in Vietnam. Some extracts from Lumnitzera racemosa leaves were reported to possess bioactivities, . antimicrobial, hepatoprotective and antioxidant. This species was traditionally used to treat asthma, diabetes and snake bite. Some reports on the chemical constituents of Lumnitzera racemosa have been reported and there had one study on the antioxidant and cytotoxic activities of this plant growing in Vietnam [3] MATERIALS AND METHOD General The NMR spectra were measured on a Bruker Avance spectrometer, at 500 MHz for 1H and 125 MHz for 13C; the HR-ESI-MS were recorded on a HR-ESI-MS MicrOTOF–Q mass Trang 20 spectrometer in the University of Science, National University – HCM City. Plant material Leaves of L. racemosa Willd. (Combretaceae)