In Vitro Antimicrobial and Antioxidant Activities of Anthrone and Chromone from the Latex of Aloe harlana Reynolds

Abstract

In the search for new antimicrobial and antioxidant compounds from plants, the latex of the medicinal plant Aloe harlana Reynolds from Ethiopia was subjected to bioassay-guided fractionation, which led to the isolation of two known compounds, anthrone (aloin) and chromone (7-O-methylaloeresin A). The latex and its two constituents were assessed for their possible antimicrobial activities against 23 bacterial and four fungal strains using the disc diffusion method and their antioxidant activity by two complementary test systems, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2-deoxyribose degradation assay methods. The isolated compounds showed promising results against various pathogenic bacterial and fungal strains in comparison with standard drugs. Moreover, 7-O-methylaloeresin A exhibited good activity against multiple drug resistant Staphylococcus aureus (NCTC 11994) and Salmonella typhimurium (ATCC 1255) with MIC values of 0.72 and 0.18 mm, respectively. Among the fungal strains tested, Candida albicans (ATCC 10231) was the most susceptible organism to the latex and the two isolated compounds. The latex and isolated compounds also showed significant activities on both antioxidant assays with the highest activity being observed for 7-O-methylaloeresin A, which gave IC(50) values of 0.026 mm and 0.021 mm for DPPH and 2-deoxyribose degradation assay, respectively. These findings support the traditional uses of the plant for the treatment of various infectious and inflammatory diseases.

Antimicrobial Activity of Fruit Latexes from Ten Laticiferous Plants

“…Similar antimicrobial activity is reported in Calotropis procera latex due to presence of Osmotin [41]. Procerain, a stable cysteine protease isolated from the latex of Calotropis procera and anthrone and chromone shows strong antimicrobial activity [11] [42]. Latex proteins prevent septic shock due to lethal infection by Salmonella enterica serovar Typhimurium [43].…”

“…Latex from Hancornia speciosa Gomes (Apocynaceae) has shown activity against Klebsiella, Pantoea, Enterobacter and Burkholderia [7] while Hevea bransilensis latex shows antifungal activity against Trichosprum cutaneum and Cryptococcus neoformans [5]. It also exhibits a good activity against multiple drug resistant Staphylococcus aureus (NCTC 11994) and Salmonella typhimurium (ATCC 1255) and Candida albicans (ATCC 10231) [11]. Similarly, antibacterial activity is reported in C. procera by Jain et al, (1996) [8].…”

“…Hevea bransilensis showed antifungal activity against Trichosporon cutaneum and Cryptococcus neoformans [5]. It also exhibit good activity against multiple drug resistant Staphylococcus aureus (NCTC 11994) and Salmonella typhimurium (ATCC 1255) and Candida albicans (ATCC 10231) [11]. The latex of fig fruit (Ficus carica) is used in traditional medicine for the treatment of skin infections.…”

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“…Latex from the A. vera plant contains aloin that contains laxative properties. [54] Latex of C. procera shows anti-arthrictic activity and cut down arthritic pain in joints [ Table 1]. [55] Korean red ginseng saponin fraction rich in gensenoside-Rb-1, Rc, and Rb2 attenuates the severity of mouse collagen-induced arthritis.…”

Synthesis and Transformation of Halochromones

“…Chromone-type compounds are well-known for their variety of biological properties, that include antitumor [4][5][6][7][8][9][10][11][12][13][14][15], hepatoprotective [16], antioxidant [17][18][19][20][21], anti-inflammatory [22][23][24][25], cardioprotective [26], antimicrobial [27,28] and antiviral activities [29,30]. The vast range of biological effects associated with these structural skeletons has led to substantial research devoted to the isolation from natural resources, synthesis and transformation of chromone derivatives and also to biological evaluation with emphasis on their potential medicinal applications.…”