Abstract:
The plant Cassia fistula is one the important medicinal plants of Bangladesh. It belongs to the family Fabaceae and genus Cassia. The plant Cassia fistula is locally known as Sonalu. It is a medium sized deciduous or semi-deciduous tree, 10 to 15 m tall with a straight trunk to 5 m in height and 1 m in diameter. The leaves are deep green, flowers are bright yellow in color. The fruit is a pendulous and cylindrical. It is black, glabrous and many seeded. Seeds are ovate, imbedded horizontally, dark colored pulp. This plant is used for the treatment of several diseases like skin diseases, abdomen pain, fever and leprosy etc.
Different types of compounds like flavonoids, glycosides, alkaloids, steroids and amino acids have been reported from the plant of the genus Cassia. Anthraquinone glycosides, kaempferol, tannins and chromen were reported from Cassia fistula. The purpose of the present research work was a phytochemical investigation on the fruits of Cassia fistula for the isolation of bioactive secondary metabolites like alkaloid, flavonoid, and chromen as well as to determine their molecular structure.
Fresh and matured fruits of Cassia fistula were collected from Sitakunda-Kumira hill region of Chittagong district during the month of December 2020. The dried powdered fruits (3 kg) were successively extracted with dichloromethane (DCM) and rectified sprite (RS). RS extract was concentrated to 250 ml and partitioned with CHCl3, EtOAC and n- butanol respectively. On the removal of the solvent CHCl3 extract gave a green Mass 31 g.
Fractionation and purification of CHCl3 extract afforded three pure compounds, named as P1, P2 and P3. Compounds P1 and P2 showed remarkable antibacterial activities against gram-positive and gram-negative bacteria and compounds P3 exhibited significant antifungal activities against the fungi Aspergillus niger. Their structure of compounds were established as 2-(1ʹ, 7ʹ - dihydroxy-2ʹ, 6ʹ - dimethylheptyl)-4H- chromen-4-one (P1), (E)-2-(1ʹ, 11ʹ -dihy droxy-4ʹ, 9ʹ -dimethylundee-6ʹ -en-1ʹ -yl)-4H-chromen-4-one (P2) and 5ʹʹ[{(2R,3S,5R,6S)-3ʹʹ,4ʹʹ,5ʹʹ-trihydroxy-6ʹʹ(hydroxymethyl)tetrahydro-2H-pyran-2-yl}oxy]-5ʹʹʹ[{(2S, 3R, 5S,6R)-3ʹʹʹ,4ʹʹʹ,5ʹʹʹ-trihydroxy-6ʹʹʹ (hydroxymethyl) tetrahydro-2H-pyran-2-yl}oxy]-17-[{(E)-17,21,25 -trimethyldodee-15-en-15-yl}oxy]-2ʹ-(28ʹ,29ʹ,30ʹ-trimethlytridecyl)--9,10ʹ-bianthracene]-9, 10ʹ (9ʹH,10H)-dione (P3)
