Chemical Investigation of Crataeva nurvala Buch. Ham. Fruits

Abstract

Chemical investigation of fruits of Crataeva nurvala has revealed the presence of four known compounds which are pentadecane, octanamide, 12-tricosanone and friedelin. These compounds have been characterized on the basis of spectral and other data. These are being reported for the first time from the fruits of this plant.

Crataeva nurvala (family: Capparidaceae) is commonly known as barna and varuna[1]. It is distributed, wild or cultivated, throughout India and tropical regions of the world[2]. Fruits are berry-like, globose or oblong; edible and used as astringent[3]. Fruiting occurs in April-June. Seeds are embedded in yellow pulp. Rind of the fruit is used as a mordant in dyeing[4]. As the fruits of the plant have not been extensively studied for chemical components, the present study was taken up.

Melting points were determined on a Ganson Electrical Melting Point Apparatus. ¹H NMR spectra were recorded on a Bruker AC 300 MHz NMR Spectrometer using TMS as an internal standard. Chemical shifts are given in δ (ppm) and CDCl₃ was used as solvent. IR spectra were recorded on a Hitachi 570 Infrared Spectrophotometer. Mass Spectra were obtained on a VG 70 S 11-250 J GCMS-DS Spectrometer.

Fruits of C. nurvala (5 kg) were collected from Botanical Gardens, HAU, Hisar. These were crushed, dried and extracted with hot methanol. The plant material (1 kg at a time) had been taken into a 5 l RB flask fitted with a water condenser for refluxing the material with MeOH. Refluxing was carried out for 6 h. The process had been repeated three times to prepare methanol extract of 5 kg of the material. The methanol extract was concentrated over water bath under reduced pressure. Extractives were subjected to silica gel (60-120 mesh) column chromatography. Four compounds were obtained.

Compound A (n-pentadecane, 1), molecular formula C₁₅H₃₂, was obtained on elution with petroleum ether as an oily liquid, 5 ml, b.p. 270°[5]. IR (KBr, v_max, cm⁻¹): 600, 800, 1026, 1261, 1378, 1441, 2362. ¹H NMR (CDCl₃, δ): 1.25 (26 H, br, 13* -CH₂-), 0.88 (6 H, t, J 7.5 Hz, 2* -CH₃). GCMS (m/z): 212 (M⁺).

Compound B (octanamide, 2), molecular formula C₈H₁₇NO, was obtained on elution with benzene-petroleum ether (1:3) as a colourless solid, 10 mg, m.p. 112° (literature m.p. 110-112°)[6]. IR (KBr, v_max, cm⁻¹): 756, 802, 1026, 1235, 1372, 1740, 2925, 3456. ¹H NMR (CDCl₃, δ): 5.13 (2 H, s, CONH₂), 2.02 (2 H, t, J 7.5 Hz, -CH₂CONH₂), 1.66 (2 H, br, -CH₂CH₂CONH₂), 1.25 (8 H, br, 4* -CH₂-), 0.88 (3 H, t, J 7.5 Hz, 2* -CH₃). GCMS (m/z): 143 (M⁺).

Compound C (12-tricosanone, 3), molecular formula C₂₃H₄₆O, was obtained on elution with benzene as a colourless solid, 10 mg, m.p. 69° (reported m.p. 68°)[6]. IR (KBr, v_max, cm⁻¹): 765, 1012, 1257, 1460, 1617, 1733, 2916. ¹H NMR (CDCl₃, δ): 2.33 (4 H, J 7 Hz, -CH₂CO-), 1.54 (4H, m, 2* -CH₂CH₂CO-), 1.26 (32 H, br, 16* -CH₂-), 0.88 (6 H, t, J 7.0 H_z, 2* -CH₃). GCMS (m/z): 338 (M⁺).

Compound D (friedelin, 4), molecular formula 426, was obtained on elution with ethyl acetate-benzene (1:19) as a colourless crystalline solid, 15 mg, m.p. 260° (reported m.p. 259-261°)[7]. It gave pale brown colour on reaction with Ac₂O/H₂SO₄. IR (KBr, v_max, cm⁻¹): 980, 1053, 1073, 1176, 1205, 1220, 1377, 1389, 1715. ¹H NMR (CDCl₃, δ): 1.25-2.31 (25 H, m, 11*-CH₂-, 3* -CH<), 1.16 (3H, s, -CH₃), 1.05 (3H, s, -CH₃), 1.01 (6 H, 2* -CH₃), 0.97 (3H, s, -CH₃), 0.88 (6H, s, 2* -CH₃). GCMS (m/z): 426 (M⁺).

The four known compounds are being reported for the first time from the fruits of this plant.