Nematicidal natural products from the aerial parts of Rubus niveus

Abstract

Studies on the aerial parts of Rubus niveus yielded six known compounds, 3,5-dihydroxy benzoic acid C₇H₆O₄, (1), gallic acid C₇H₆O₅ (2), ethyl galactoside (3), oleanolic acid (4), β-sitosterol (5) and 3-O-[β-D-galactopyranosyl-(12)-D-glucopyranoside (6). Besides this, a gallic acid derivative with methyl substitution was synthesised as tetramethyl gallate (3). Together with this derivative, compounds 1, 2, the alcohol soluble, chloroform soluble and petroleum ether soluble extracts of the aerial parts of R. niveus were screened for its nematicidal activity against freshly hatched second stage juveniles of Meloidogyne incognita (root-knot nematode), exhibiting 100, 94, 100, 52, 45 and 14% mortality, respectively of M. incognita after 48 h at 0.5% concentration. Compounds 1, 2 and 3 were found to be more potent than the nematicide Azadirachta indica at the same concentration. Negative results were obtained for nematicidal activity of the petroleum ether extract of R. niveus leaf extract. This is the first report on the isolation of chemical constituents as well as the nematicidal activity of compounds and any part of R. niveus.

Keywords:

• Rubus niveus
• nematicidal activity
• 3,5-dihydroxy benzoic acid
• ethyl galactoside
• tetramethyl gallate
• gallic acid