Two new alkaloids and a new polyphenolic compound from Cotula coronopifolia

Abstract

Two new alkaloid derivatives of the 3-benzazocine skeleton (cotuzine A and B) and a new polyphenolic substance (3-(1,3-dihydroxyprop-2-yl)-4-hydroxyanisol) (corimen) have been isolated from the aerial part (stems, leaves) of the plant Cotula coronopifolia (L.). These three new structures were established by spectroscopic procedures ( 1 H, 13 C,. The stereochemistry of the new alkaloids was established based on different NOE effects revealed on the NOESY spectrum. Mass spectrometry and IR spectroscopy were used to confirm these structures.The interest in nature as a source of potential chemotherapeutic agents continues. Natural products and their derivatives represent more than 50% of all drugs in clinical use in the world. Higher plants contribute no less than 25% of the total [1]. As part of our chemical investigation into some medicinal plants growing in Tunisia [2][3][4] and in order to continue our search for potential biological natural compounds [5], we report here the isolation and structure elucidation of two new alkaloids 1 and 2 and a new polyphenolic compound 3 isolated from the aerial part of Cotula coronopifolia (L.) (Asteraceae). So far not much is known on the ethnopharmacology of this plant [6].Structures of cotuzine A and B (1, 2) and corimen (3) were established by spectroscopic means (1D and 2D NMR) and confirmed by comparison with those of closely related compounds [7,8]. The relative stereochemistry of the alkaloid structure was obtained from the NOESY experiment.Cotuzine A (1) was obtained as an amorphous solid (29 mg) from the butanolic extract of the aerial part (stems, leaves) of the plant Cotula coronopifolia (L.). The IR spectrum indicated the presence of hydroxyl groups (3400-3200 cm -1 ), methyl groups (2963, 2882 cm -1 ), secondary amines (3029, 827 cm -1 ), and double bonds (3021, 1651 cm -1 ). The 13 C NMR spectrum (Table 1) indicates the presence of 21 carbons, including an ethylenic group relative to C-6 and C-6a at 119.9 ppm and 144.6 ppm, respectively, an anomeric carbon at 103.7 ppm, and two (-CH 2 -) groups at 40.5 and 42.2 ppm forming the (-CH 2 -NH-CH 2 -) skeleton. The 1 H NMR spectrum shows a signal at G 5.22 ppm attributable to H-6 coupled with H-5D 1.91 ppm, m) and H-5E (1.83 ppm, m), a doublet relative to CH 3 -8 0.89 ppm, d, J = 6.8 Hz), and three signals relative to three methyl groups: CH 3 -7D 0.91 ppm, s), CH 3 -7E 1.04 ppm, s), and CH 3 -10 0.91 ppm, s).

A new sulfonylated flavonoid and other bioactive compounds isolated from the aerial parts of Cotula anthemoides L.

“…In addition, it has been reported as antipyretic (Larhsini et al, 2002), bacteriostatic (Jana et al, 1992), antiprotozoal (Markouk et al, 1999) and anticorrosive (Benmenine et al, 2011). Several flavonoids (Ahmed et al, 1987;Mahran et al, 1976), alkaloids (Mahjoub et al, 2012), sesquiterpene lactones (Jakupovitch et al, 1988;Metwalli et al, 1986) and coumarins (Greger et al, 1985) were isolated from this genus. Cotula anthemoides L commonly known as 'Babunaj' in Algeria is used for colic and as a remedy for head and chest colds (Abhay and Tripathi, 2011).…”