Mangifera indica peels: A common waste product with impressive immunostimulant, anticancer and antimicrobial potency

Abstract

The volatile components of 3 mango cultivars were investigated by means of GC, and GC-MS. Two hundred and forty compounds were identified, of which eighty five compounds were found for the first time in mango fruit. Terpene hydrocarbons were the major volatiles of all cultivars, the dominant terpenes in the 3 mango cultivars were ?-3-carene (2.784-14.904%), ?-terpinolene (4.825-15.879%), ?-copaene (2.281-8.097%), and caryophyIlene (3.390-10.897%). peel essential oils of M. indica cultivar zebdeya and M. indica cultivar cobaneya showed appreciable non specific immunostimulant activity measured by low Macrophage migration index. M. indica cultivar zebdeya and M. indica cultivar cobaneya had higher phagocytic indices up to 1.47and 1.06 respectively. The cytotoxicity of the essential oils were studied invitro against MCF-7, HCT-116 and Hep-G2 cancer cell lines using MTT assay showed significant effect with IC₅₀ = 1.62-1.77, 2.95-5.56 and 2.76-3.14 µl/ml for respectively. Interestingly, M. indica cultivars zebdeya, cobaneya and hindi expressed a valuable cytotoxic effect on MCF-7 breast carcinoma cell line as compared to standard antitumor drug.

The essential oils M. indica cultivars were tested by Kirby-Bauer method showing a wide range of antibacterial and antifungal activities. Generally, essential oils of the M. indica cultivars showed a moderate to high antibacterial activity with M. indica cultivar hindi being the most active showing broad spectrum activity against Gram-positive (18-21 mm) and Gram-negative bacteria (16-19 mm). It also showed significant antifungal activity against Candida albicans (16 mm); however, data revealed that all tested cultivars were ineffective and have no antifungal activity against Aspergillus flavus.

The MIC of the three M. indica cultivars essential oils revealed that although essential oils didn’t show antimicrobial activities against Aspergillus flavus the peel essential oils demonstrated variability in the inhibitory concentrations of each essential oil for the given microorganisms. The essential oils of peels showed activities in the range (concentrations) from 116 to 142 ?l/ml for M. indica cultivar zebdeya, 58 to 89 ?l/ml for M. indica cultivar hindi and from 121 to 172 ?l/ml for M. indica cultivar cobaneya. The present investigation proved the possibility of using M. indica peel waste as a source of low-cost natural immunostimulant, anticancer and antimicrobial.

Key words: Mangifera indica peels; waste product; immunostimulant, anticancer; antimicrobial