Flavonoids from the twigs of Cynometra cauliflora Linn

Cynometra cauliflora Linn, a member of the bean family Fabaceae, with vernacular name 'nam-nam', was believed to be native of Malaysia and cultivated in Indonesia and India[1]. C. cauliflora is a small, much-branched perennial tree growing to 5 m tall. It is a typical underutilized fruit tree that has the medicinal values in folk traditional medicine in treating several diseases and cultivated as an ornamental plant in the village. A decoction of the leaves is traditionally used for treating diabetes and hyperlipidemia, the fruits for curing the lost of appetite, and the seed oil is used to cure skin diseases. Previous works have been done on anti and pro-lipase activity which lead to the isolation of kaempferol-3-O-rhamnoside as an active constituents from the plant leaves [2]. Other study reported their chemical profile with antiacetylcholinesterase, antityrosinase, antioxidant and α-glucosidase inhibitory activities of its leaves extract [3]. This study focused on investigating the constituents from the twigs part of this plant. The dried twigs of Cynometra cauliflora L. was macerated in acetone to obtain crude extract and fractionated using vacuum liquid chromatography (VLC). The isolation and purification of the chosen fractions by a combination of multiple radial and preparative thin layer (pTLC) chromatographic techniques afforded four pure compounds which consist of three flavones, luteolin (1), acatecin (2), 3',4',7-trihydroxyflavone (3) and one flavanone, eriodictyol (4). The structures of 1 – 4 were elucidated on the basis of 1D NMR and 2D NMR correlations and comparison with previous literature.

Fig. 1

[1] Seidemann J. World spice plants. Springer: Berlin-Heidelberg, 2005, 131.

[2] Ado MA, Abas F, Mohammed AS, Ghazali HM. Molecules2013, 18:14651 – 14669.

[3] Ado MA, Abas F, Ismail IS, Ghazali HM, Shaari K. J Sci Food Agric: Wiley2014, 1 – 8.