Antiplasmodial Activity of Lignans and Extracts fromPycnanthus angolensis

Abstract

The dichloromethane, methanol and aqueous ethanol extracts of the stem bark of Pycnanthus angolensis were evaluated for their in vitro activity against the 3D7 Plasmodium falciparum strain. The CH (2)Cl (2) extract was the most active showing an IC (50) = 1.6 microg/mL. From this extract, a new dibenzylbutane lignan, threo-4,4'-dihydroxy-3-methoxylignan ( 1) named pycnantolol, together with the known lignans (-)-dihydroguaiaretic acid ( 2), heliobuphthalmin ( 3), talaumidin ( 4), hinokinin ( 5), the labdane-type diterpene ozic acid ( 6), and the steroids stigmast-4-en-6beta-ol-3-one ( 7), beta-sitosterol ( 8) and stigmasterol ( 9) were isolated. Their structures were established on the basis of physical and spectroscopic methods, including 2 D NMR experiments (COSY, HMQC, HMBC and NOESY). The antimalarial activity of compounds 1 - 7 was evaluated against 3D7 and Dd2 P. falciparum strains. Despite the significant activity displayed by the crude CH (2)Cl (2) extract, the isolated compounds showed weaker antiplasmodial activity. The lowest IC (50) value was obtained for talaumidin ( 4) (IC (50) = 20.7 microg/mL against the Dd2-chloroquine resistant P. falciparum strain).

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“…Warb. Zirihi et al (2005) Lignans (Abrantes et al, 2008), terpenoids quinines (Wabo et al, 2007), isoflavonoids (Omobuwajo et al, 1992) …”

A review of antimalarial plants used in traditional medicine in communities in Portuguese-Speaking countries: Brazil, Mozambique, Cape Verde, Guinea-Bissau, São Tomé and Príncipe and Angola

“…Dichloromethane, methanol and aqueous ethanol extracts of P. angolensis barks were evaluated for their in vitro antimalarial activity and dichloromethane extract was the most effective (IC 50 of 1.6 μg/mL) (Abrantes et al 2008).…”

Antiplasmodial Activities of the Stem bark Extract and Compounds of Zanthoxylum gilletii (De wild) P.G. Waterman

“…77 Other classes of lignans including: tetrahydrofuran lignans, neolignans, dibenzylbutanelignan and a coumarinolignan also demonstrated varying degrees of antimalarial activities against mainly P. falciparum with tetrahydrofuran-type sesquilignans revealing significant activities. [78][79][80][81][82] Compound 3 was also active against the three strains of the malaria parasite tested with IC 50 …”