2.4. Isolation from the Stem Bark of Acacia polyacantha

The stem bark crude extract (135.59 g) of Acacia polyacantha was partitioned between AcOEt (750 mL × 3) and n-butanol (750 mL × 3) to give 36.2 g of AcOEt and 54.7 g of n-BuOH fractions. The ethyl acetate fraction (36.2 g) was adsorbed on an equivalent mass of silica and chromatographed over a silica gel column chromatography (40–63 μm, 4.5 × 50 cm) using n-hexane-AcOEt and CHCl₃-MeOH gradients as eluents. Fractions of 250 mL each were collected as follows: [(1–3), n-hexane 100%], [(4–8), n-hexane-AcOEt 5%] [(9–15), n-hexane-AcOEt 10%], [(16–33), n-hexane-AcOEt 15%], [(34–46), n-hexane-AcOEt 20%], [(47–57), n-hexane-AcOEt 30%], [(58–60), n-hexane-AcOEt 50%], [(61–63), CHCl₃-MeOH 5%], [(64–70), CHCl₃-MeOH 10%], and [(71–85), CHCl₃-MeOH 15%]. These fractions were combined on the basis of their TLC profiles to give 13 subfractions (F₁-F₁₂) as follows: F₁ (1–5, 5.3 g), F₂ (6–8,4.2 g), F₃ (9–14, 4.3 g), F₄ (15–24, 1.1 g), F₅ (25–32, 2.8 g), F₆(33–42, 2.2 g), F₇ (43–49, 1.5 g), F₈ (50–55, 2.7 g), F₉ (56–64, 2.9 g), F₁₀ (65–69, 1.5 g), F₁₁ (70–75, 2.4 g), and F₁₂ (76–85, 4.1 g). Compound 8 (123.2 mg) was isolated as white crystal by filtration of the precipitates of the subfractions F₂. Compound 9 (12 mg) was isolated as a white powder by filtration of the precipitates of the subfractions F₇. From F₈, compound 10 (10.5 mg) was obtained as a white powder. This extract (135.5 g) gave a yield percentage of 5.42%.