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

Antimycotic activity

Lawsone has been shown to be effective against oral Candida albicans isolated from patients with HIV/AIDS (Prasirst 2004). We have reported activity against Candida albicans using Omani henna (Habbal 2005). During antifungal screening of higher plants, the leaves of Lawsonoia inermis were found to exhibit strong fungitoxicity where naphthoquinones were found to be the active factor (Tripathi 1978).

Fungotoxic studies against ringworm fungi were demonstrated. Barks of 30 plant species were screened against Microsporum gypseum and Trichophyton mentagrophytess; only Lawsonia inermis exhibited absolute toxicity (Singh 1989). The Lawsonia bark extract was found to possess a fungistatic nature at its maximum inhibitory dilution of 1:30 (W/V) against both test pathogens, but became fungicidal at 1:10 (W/V) (Bogdanov 1993).

The extract showed broad fungitoxic spectrum when tested against 13 ringworm fungi (Singh 1989). This role of a cosmetic and antimycotic has been reported by others (Itani 1973).

Molluscicidal activity of leaf, bark and seed of Lawsonia inermis against Lymnaea acuminata and Indoplanorbis exustus was studied with the highest toxicity observed in the seed of the plant (Singh 2001).

Virucidal activity

Bhandarkar and Khan (2003) suggest hepatoprotective and antioxidant activity of extract of Lawsonia alba Lam. against hepatic damage in albino rats. This may indirectly indicate an important role of henna as an antiviral agent. Hepatitis related viruses such as hepatitis C virus (HCV) and hepatitis E virus (HEV), and the new infectious diseases such as the Ebola virus, Legionella pneumophila and human immunodeficiency virus (HIV), have been discovered in the past 20 years. The emergence of drug resistant strains is a big challenge that faces antibacterial medicine.

The ethanol extract of Lawsonia inermis was studied (Mouhajir 2001) along side 75 other Morocaon plants that are used traditionally to treat diseases that could be caused by viruses and microbes. These plants were tested against three mammalian viruses: herpes simplex virus, Sindbis virus and poliovirus, at non toxic concentrations. Lawsonia inermis extract inhibited Sindbis virus at a minimum concentration of 1.5 4g/mL. Such findings indicate that the plant is a potentially potent drug against infectious diseases caused by viruses.

However in the same study the discriminatory effect of various plants against specific microorganisms suggests the presence of different chemical compounds. Light is a determining factor in the activity of photosensitisers and should be taken into account in this kind of work.

Quinones include various quinine derivatives including naphthoquinones. The multi quinine compounds can include identical quinine monomers or two or more different quinine monomers. Trimeric naphthoquinones were found to inhibit the growth and replication of viruses, particularly retroviruses such as HIV (Koyama 2006). The inhibitory activity of some naphthoquinones on RNase H activity associated with HIV-1 reverse transcriptase has been described (Min 2002).