New bioactive compounds fromAloe hijazensis

Abstract

The chemical constituents and biological activities of leaves and roots of Aloe hijazensis, collected in Saudi Arabia, are reported here for the first time. Twenty-two compounds were obtained, among them eight hydroxyquinones: aloe-emodin (1), emodin (2), chrysophanol (3), aloesaponarin II 3-methyl ether (4), ziganein (5), ziganein-5-methyl ether (6a), aloesaponarin I (7) and chrysophanein (8), the dihydro-isocoumarin feralolide (9), 4,7-dichloro-quinoline (10), the triterpene lupeol (11), the anthrone aloin (12), three aloenin derivatives, aloenin (13) ethylidene-aloenin (14), and aloenin B (15), four flavonoids, quercetin (16), kaempferol (17) cosmosiin (18) and isovitexin (19), and cinnamic acid (20) and two further analogues, caffeic acid (21) and ferulic acid (22). While 15 of the isolated compounds were found in the leaves, 12 were isolated from roots of the plant. Compounds 6a and 10 are reported as new natural constituents, while the compounds 4, 5, 8, and 18 are reported here for the first time from Aloe spp. The structures of the compounds were deduced by intensive studies of their UV, NMR, MS data and by comparison with related structures. The biological activity of plant extracts was studied against various microbial strains, and potent anti-bacterial and anti-fungal activities were found. [image omitted] [image omitted].

Seven naphtho-γ-pyrones from the marine-derived fungus Alternaria alternata: structure elucidation and biological properties

“…The 1 H NMR spectra (Table 2) displayed a chelated hydroxyl group ( δ 14.96), two m- coupled doublets ( δ 6.56, 6.38) and two singlets ( δ 6.94 and 5.98), along with two methoxy signals ( δ 3.99, 3.91) and an sp 2 linked methyl ( δ 2.35). The 13 C/HMQC spectra (Table 2) indicated the presence of 16 carbon signals, including 4 sp 2 methines ( δ 107.3-97.2), 3 sp 2 -oxy carbons ( δ 162.6-160.6), 1 carbonyl of γ -lactone ( δ 184.2) [20], 5 non-oxygenated sp 2 , 2 aromatic-attached methyl ethers ( δ 56.0, 55.4) and 1 sp 2 -attached methyl ( δ 20.6). Full assignment of the 2D NMR experiments (Figure 2 and Table 2) established the structure of 2 as rubrofusarin B, and excluded the structure of the isomeric asperxanthon ( 11 ) in the same way [21].…”

Beneficial health effects of lupeol triterpene: A review of preclinical studies

“…Lupeol is reported to inhibit the growth of a several types of bacteria, fungi and viral species (Hernández-Pérez et al, 1994;Ajaiyeoba et al, 2003;Tanaka et al, 2004;Erazo et al, 2008;Shai et al, 2008;Abd-Alla et al, 2009;Ahmed et al, 2010). Lupeol has been found to act as an effective anti-bacterial agent when tested against both gram positive and gram negative bacteria (Erazo et al, 2008;Ahmed et al, 2010).…”

“…Lupeol has been found to exhibit antimicrobial activity against a wide range of commonly encountered microbes (Hernández-Pérez et al, 1994;Ajaiyeoba et al, 2003;Tanaka et al, 2004;Erazo et al, 2008;Shai et al, 2008;Abd-Alla et al, 2009;Ahmed et al, 2010). Lupeol is reported to inhibit the growth of a several types of bacteria, fungi and viral species (Hernández-Pérez et al, 1994;Ajaiyeoba et al, 2003;Tanaka et al, 2004;Erazo et al, 2008;Shai et al, 2008;Abd-Alla et al, 2009;Ahmed et al, 2010).…”

In Vitro Screening for Cytotoxic Activity of Herbal Extracts

“…A systematic fractionation of an ethanol-water (1 : 1) extract of the seeds of Rhamnus Frangula , guided by assays for tumor-inhibitory activity, led to the isolation of aloe emodin [21]. This compound was found to show significant antileukemic activity against the P-388 lymphocytic leukemia in mice [22].…”