cytotoxicity and antitubercular activity of allium sativum and lantana camara against mycobacterial isolates from people living with HIV/AIDS

摘要

The Antitubercular activity of Allium sativum and Lantana camara on multiple-drug-resistant Mycobacterium was investigated among Nigerian HIV-infected-persons. Minimal inhibitory concentration (MIC) was estimated by the well-in-agar-diffusion method and potency of extracts compared with standard drugs. Cytotoxicity was determined using brine shrimps. MIC of drugs was 0.33mg/ml, 0.25mg/ml and 0.20mg/ml for streptomycin, isoniazide and rifampicin. L. camara had MIC of 0.63mg/ml for M. tuberculosis and Unidentified M. avium complex and 0.89mg/ml for M. avium Complex while garlic had 0.64mg/ml for M. tuberculosis, 0.97mg/ml for M. avium Complex and 1mg/ml for Unidentified species. LC50 of garlic was 49.1 ppm for M. tuberculosis, 56.5ppm for M. avium complex and 63.0ppm for the Unidentified species, while L. camara had 32.6ppm for M. tuberculosis, 55.9ppm for M. avium complex and 51.3ppm for Unidentified species. The observed activity of the extracts is consistent with their use in traditional medicine for the treatment of Mycobacterium species. Introduction Tuberculosis (TB), by members of the Mycobacterium tuberculosis complex, causes three million deaths a year worldwide 1. The disease is associated with impoverished economic conditions. The resurgence of M. tuberculosis infection in the developing countries is due to immigration, the emergence of drug-resistant strains, inadequate treatment, continuing poverty, malnutrition, overcrowding, alcoholism and the AIDS epidemic 2. In advanced stages of AIDS, where TB infections are commonly found, Mycobacterium infections due to members of the M. avium-intracellulare complex (MAC) are also on the increase. Thus the Morbidity and Mortality Weekly Report of the Centre for Disease Control (CDC), in 1998, declared tuberculosis a deadly disease, and the major cause of death of immune suppressed persons and especially those living with HIV/AIDS. 3 Of the 34.3 million persons living with HIV/AIDS, 24.5 million (71%) live in sub-Saharan Africa and approximately one-third of them are co-infected with tuberculosis.4 Treatment of TB involves a long period of drug administration, usually lasting for 6-24 months for effective elimination of the bacilli from the lungs, organs and macrophages. However, the drug-resistance of the pathogen has necessitated combination therapy of at least two drugs: isoniazide (INH), rifampicin, ethambutol, streptomycin, pyrazinamide and paraaminosalicyclic acid (PAS). WHO on the other hand recommends the short course directly observed therapy (DOTS) using a combination of isoniazide, rifampicin, pyrazinamide and ethambutol on a daily dose for 2 months, followed by 4 months therapy of isoniazide and rifampicin given thrice weekly.5 Garlic (Allium sativum), is the most extensively studied herb for inhibition of infections. Its antimicrobial activity was first noted in 1944 by 6 and since then, garlic extract has been considered an effective alternative for the treatment of various infections including TB and MAC infections.7 All parts of this plant have been used traditionally for several ailments throughout the world. The leaves are used as a bechic, antitumoural, antibacterial and antihypertensive agent. The root of this plant is used for the treatment of malaria, rheumatism and skin rashes: dermatitis, eczema, pruritis.8 It is also indicated for influenza, cough, mumps, high fever and tuberculosis 9; and has also been shown to be helpful in gum care.10 The medicinal efficacy of L. camara has been widely reported. Its rich phytochemical components including cardiac glycosides, useful in enhancing mycocardiac contraction as welll as the present alkaloids, flavonoids and other essential oils are indicative of its antioxidant activity. 11-12 The root has established uses in malarial control, rheumatism, skin rashes as well as dermatitis, eczema, and related mycotic infections as well as in the management of respiratory tract infections including influenza, and tuberculos