Antimicrobial properties of Lawsonia inermis : a review

Australian Journal of Medical Herbalism, Fall, 2007 by O.A. Habbal, A.A. Al-Jabri, A.G. El-Hag

Many naphthoquinones have been isolated but frequently their potential use has been limited by low bioavailability and high toxicity (Wright 1990). Activity and mutagenicity of bisbenzylisoquinolines and quinones against Trypanosomacruzi trypomastigotes were reported to have no structure activity relationship (De Arias 1994). The only active naphthoquinone, plumbagin is an antiprotozoal compound with activity against Leishmania anzazorzensis and Leishmania doizovani in vitro and in vivo (Croft 1985; Fournet 1992) and antibacterial and antifungal activities (Gujar 1990). A dimeric naphthoquinone diospyrin from Diospyros montana (Ebenaceae) was found to be active against Leishmania donovani (Ardley 1996). The inhibition of Type I DNATopoisomerase in this parasite has been suggested as a mechanism of action (Tazi 2005).

Anthraquinones and xanthones are naturally occurring product groups which are related to naphthoquinones in structure and biological activity (Thomson 1991). The main chemical difference between the groups is the tricyclic aromatic system with a paraquinoid substitution (Schnur 1983). Some derivatives have activity in vitro against Leishmania spp (Fournet 1992) but few naturally occurring anthraquinones have been tested.

Anti-carcinogenic activity of henna

Henna's anticarcinogenic property was reported (Endrini 2002) using a chloroform extract of Lawsonia inermis by the culture tetrazollium salt (MTT) assay on the human breast, colon and liver carcinogenic cell lines and normal human liver cell lines (Endrini 2002).

The preliminary results showed that henna extract displayed cytotoxic effects against HepG2 (liver cells) and MCF-7 (hormone dependent breast cells), but no significant activity was recorded against colonic, hormone nondependent breast cell lines and normal liver cells at the concentrations tested. These results indicate the selectivity of such cytotoxic activity.

The antioxidative activity of this henna extract was found to be highest compared to vitamin E or [alpha]-tochopherol, attributing to the strong cytotoxic activity of the extract (Endrini 2002). Additionally inhibition of malignant cell growth in culture by quinones using HCT-15 cells derived from human colon carcinoma was shown to be due to lawsone as a member group of the quinone group (Kamei 1998).

This appears to be achieved by blocking the S-phase of cell cycle. The protective role of henna was also reported using an ethanol-water extract (1:1) against CCl4-induced liver toxicity in mice (Anand 1992).

Dichloroallyl lawsone (DCL, NSC-126771) (McKelvey 1979), a synthetic analogue of the antimalarial lapachol, is potentially useful in cancer chemotherapy (McKelvey 1979). Unlike most anticancer agents DCL is not significantly myelosuppressive in animals but it induces acute cardiac toxicity in the rhesus monkey (McKelvey 1979). This cardiac toxicity seems to be correlated with the maximal plasma DCL concentration, about 130 mg/L in the monkey. McKelevy et al (1979) have tested the DCL pharmacokinetics in patients in an attempt to define safe dose limits for the Phase I clinical trial. After the rapid intravenous infusion of 10 mg/m2 of radioactive [1- or 4-14C]DCL, 250 muCi per patient, the mean peak plasma concentration of unchanged DCL in four patients was 2.9 /- 0.3 mg/L.