Neolignans and Other Metabolites from Ocotea cymosa from the Madagascar Rain Forest and Their Biological Activities

Abstract

Ten new neolignans including the 2′-oxo-8.1′-lignans cymosalignans A (1a), B (2), and C (3), an 8.O.6′-neolignan (4a), ococymosin (5a), didymochlaenone C (6a) and the bicyclo[3.2.1]octanoids 7–10 were isolated along with the known compounds 3,4,5,3′,5′-pentamethoxy-1′-allyl-8.O.4′-neolignan, 3,4,5,3′-tetramethoxy-1′-allyl-8.O.4′-neolignan, didymochlaenone B, virologin B, ocobullenone and the unusual 2′-oxo-8.1′ –lignan sibyllenone from the stems or bark of the Madagascan plant Ocotea cymosa (Lauraceae). The new 8.O.6′-neolignan 4a, dihydrobenzofuranoid 5a, and the bicyclo[3.2.1]octanoid 7a had weak in vitro activity against Aedes aegypti, while the new compounds 5a, 7a, 8 and 10a and the known virolongin B (4b) and ocobullenone (10b) had antiplasmodial activity. We report herein the structure elucidation of the new compounds on the basis of spectroscopic evidence, including 1- and 2-D NMR spectra, Electronic Circular Dichroism (ECD), and mass spectrometry, and the biological activities of the new and known compounds.

Recent advances in research on lignans and neolignans

“…114 Compound 485 was reported from the stem or bark of Ocotea cymosa. 152 Its conguration was tentatively assigned as S based on its positive optical rotation, as for synthetic (S)-virolongin B, a closely related compound even though the magnitude of the rotations differed signicantly. Compounds 486-489 are stereoisomers sharing a common planar structure isolated from the roots of Paeonia lactiora by chiral HPLC.…”

“…The bark of the Madagascan plant Ocotea cymosa afforded compounds 527-530 together with the 6 0 -oxo-8.1 0lignans cymosalignans A-C (531-533) and didymochlaenone C (534). 152 Compounds 527-530 belong to a rare group of bicyclo [3.2.1]octanoid neolignans possessing a 7.1 0 .8.3 0 coupling with unique features such as the deoxygenated C-2 0 between the bridge heads and the methylenedioxy group on the cyclohexenone ring. The relative and absolute congurations of 531-533 were not assigned.…”

Bioactive Neolignans and Other Compounds from Magnolia grandiflora L.: Isolation and Antiplasmodial Activity

“…Thus several lignans with antiplasmodial activity from African medicinal plants are reported in the review by Ntie‐Kang et al ., and lignans with antiplasmodial activity have been reported from Asparagus africanus and Carrisa edulis . Neolignans have also shown good antiplasmodial activity . One point of interest is that antiplasmodial activity appears to be strongly dependent on the substitution pattern of simple lignans.…”

“…[26] Neolignans have also shown good antiplasmodial activity. [27] One point of interest is that antiplasmodial activity appears to be strongly dependent on the substitution pattern of simple lignans. Thus compounds 3 and 4 were active at the single digit micromolar level, but compound 5, isomeric with 4, was fivefold less potent, and compound 6, with an extra OH group, was thirty-fold less potent than 3.…”

Chemical Composition, Antiprotozoal and Cytotoxic Activities of Indole Alkaloids and Benzofuran Neolignan of Aristolochia cordigera

“…Other interesting classes of chemical compounds obtained from Aristolo-chia are lignans and neolignans. Compounds belonging to these classes have shown a variety of biological activities, such as insecticidal [3,4], insect feeding deterrent [5], antitubercular [6], antimycobacterial [6], antiplasmodial [7][8][9], antileishmanial [10], and trypanocidal [11]. In addition, several lignans and neolignans are known for their neuroprotective effects, inhibition effect of nitric oxide production, prevention of oxidative stress-induced neuronal death, and antagonism to the neurotropic effect of scorpion venon [12][13][14][15].…”