10.

Highly Oxygenated Flavonoids from the Leaves of Nicotiana plumbaginifolia (Solanaceae)

Department of Pharmacy, Stamford University Bangladesh, 51 Siddeswari Road, 1217 Dhaka, Bangladesh

Pharmaceutical Sciences Research Division (PSRD), Bangladesh Council for Scientific and Industrial Research, Dhaka-1205, Bangladesh

Department of Pharmaceutical Chemistry, University of Dhaka, Dhaka-1000, Bangladesh

Medicinal Chemistry and Natural Products Research Group, School of Pharmacy and Biomolecular Sciences, Faculty of Science, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, United Kingdom

Abstract: Nicotiana plumbaginifolia Viv. is an annual herb of the family Solanaceae, which grows abundantly in the weedy lands of Bangladesh . This plant possesses analgesic, antibacterial, anti-anxiety and hepatoprotective properties, and produces various phenolic compounds including flavonoids. The present study afforded determination of total phenolic and flavonoid contents, and for the first time, the isolation and characterization of highly oxygenated flavonoids, e.g., 3,3' ,5,6,7,8-hexamethoxy- 4',5'-methylenedioxyflavone (1), 3,3' ,4' ,5',5,6,7,8-octamethoxyflavone (2, exoticin), 6,7,4',5'-dimethylenedioxy-3,5,3'-trimethoxyflavone (3) and ( 3,3' ,4',5,5',8-hexamethoxy-6,7-methylenedioxyflavone (4) from the leaves of N. plumbaginifolia . All these flavonoids are rather rare natural products, and only found in a few genera, e.g.,Polygonum and Murraya. The structures of the isolated flavonoids were elucidated by comprehensive spectroscopic analyses, e.g., UV, 1H, 13C NMR, DEPT, HSQC, HMBC and MS.

Keywords: Highly oxygenated flavonoids;Nicotiana plumbaginifolia ;Solanaceae; phenolics; NMR. © 2017 ACG Publications. All rights reserved.