Antibacterial and Antioxidant Compounds from the Root Extract of Aloe debrana.

This study was conducted to isolate and identify the chemical compounds from the roots of Aloe debrana (L.) and evaluate their antioxidant and antibacterial activities. From the acetone (99.5%) extract of the roots of this plant, four anthraquinones, such as chrysophanol (1), asphodeline (2), aloesaponarin I (5), and laccaic acid D-methyl ester (6), and a new catechol derivative, 5-allyl-3-methoxybenzene-1,2-diol (3), were isolated and elucidated by different chromatographic and spectroscopic methods together with linoleic acid (4), respectively. Compounds 2, 3, and 4 were reported here for the first time from this plant and compound 3 from the genus Aloe. The compounds were evaluated for their antioxidant activity using H2O2 and DPPH assays and bactericidal activity against S. aureus and E. coli. Compounds 3 and 6 showed highest antioxidant activities with IC50 values of 19.38 ± 0.64 and 32.81 ± 0.78 µg/mL in DPPH, and 28.52 ± 1.08 and 27.31 ± 1.46 µg/mL in H2O2, respectively. The isolated compounds also demonstrated considerable activity towards S. aureus. Among these compounds, compound 3 exhibited the highest activity (91.20 ± 0.12% and 9.14 ± 0.93 mm at 1.0 mg/mL) against this bacterium. The overall results suggest that the isolated compounds may be considered as potential sources of the bioactive agents to be used in the pharmacological, food, and other industries. Moreover, their high sensitivity against S. aureus may also support the use of A. debrana plant in the traditional medicine to treat wounds. Therefore, the isolated compounds are responsible for medicinal properties of this plant.

Electrochemical behavior, antimicrobial activities, and effect of temperature on micellization of imidazolium monomeric surfactants.

In the present study, we herein report the conductance behavior, effect of temperature, and chain-length of two environmentally friendly imidazolium cationic capric and stearic surfactants. The conductance behavior has been carried out in aqueous solvent (H2O) at four different temperatures such as 24 °C, 29 °C, 34 °C, and 39 °C. The normal micelles were formed in an aqueous solvent and critical micelle concentration (CMC) can be estimated through conductivity parameters. The expected dependency of the CMC on the alkyl chain length of the 3-(2-(decanoyloxy)ethyl)-1-methyl-1H-imidazol-3-ium-bromide and 3-(2-(octadecanoyloxy)ethyl)-1-methyl-1H-imidazol-3-ium-bromide was demonstrated. It was observed that the graphs of molar conduct activity v/s square root were not linear, which specifies that the synthesized surfactants behave as weak electrolytes in the dilute solutions. The electrochemical characterization of capric and stearic surfactant modified SPCE was studied in 1mM K3FeCN6 solution. The CS/SPCE and SS/SPCE were shown elevated sensitivity, high stability, and excellent conductivity. Moreover, the antimicrobial behaviors of the synthesized imidazolium cationic surfactants versus various microbial strains were evaluated. Results showed that capric surfactant demonstrated high antibacterial activity against Escherichia coli (MIC > 31.5 µg/mL).

Chemical compositions and biological activities of the oils from the genus Taxus and factors limiting the regeneration of endangered yews: a review.

The genus Taxus (yews) is the largest genus of the family Taxaceae. It comprises about 24 species with 55 varieties distributed mainly in Asia, Europe, North Africa, and North America. In addition to the taxane diterpenoids and the cancer drug taxol, its species contain many essential oils with actual or potential biological activity. This review covers the chemical constituents as well as biological activities of these oils that have been studied in fourteen countries over 46 years (1975-2021). It also discusses the biotic and abiotic factors that limit the regeneration of these economically and medicinally important plants.

Chemical composition, and antibacterial and antioxidant activities of essential oils from Laggera tomentosa Sch. Bip. ex Oliv. et Hiern (Asteraceae).

Laggera tomentosa Sch. Bip. ex Oliv. et Hiern (Asteraceae), an endemic Ethiopian medicinal plant, is traditionally used to treat various ailments. Previously, the chemical constituents of the essential oil (EO) of its leaves and inflorescence were documented. However, no data about the chemical compositions of other parts of the EOs of the plant have been reported to date. Moreover, there are no previous biological activity reports on any parts of the EOs of this plant. Thus, in this study, the EOs were isolated from the stem bark and roots of this plant by hydrodistillation and analyzed using gas chromatography-mass spectrometry to identify their components. In addition, antibacterial potentials of the oils were evaluated using the disc diffusion and minimal inhibitory concentration (MIC) methods. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide methods were also employed to assess their antioxidant properties. Oxygenated monoterpenes (71.82% and 77.51%), of which 2,5-dimethoxy- p -cymene (57.28% and 64.76%) and thymol methyl ether (9.51% and 8.93%) were identified as major components in the EOs of stem bark and roots of L. tomentosa and the oils, were the most potent in the DPPH (IC50, 0.33 ± 1.10 and 0.39 ± 0.97 mg/mL) assay, respectively. Moreover, the EOs demonstrated appreciable activity towards the gram+ ( S. aureus and B. cereus ) bacteria. Among these oils, the oil of the stem bark showed the greatest activity to the gram+ (MIC = 0.625 mg/mL) bacteria. Therefore, the overall results suggested that the EOs of L. tomentosa may be a promising prospect for pharmaceutical, food, and other industrial applications.

The genus Laggera (Asteraceae) - Ethnobotanical and Ethnopharmacological Information, Chemical Composition as well as Biological Activities of Its Essential Oils and Extracts: A Review.

Most species of the genus Laggera are often used in traditional and folk medicines for the treatment of jaundice, inflammation, leukemia, removing phlegm, bronchitis and bacterial diseases. The essential oils obtained from Laggera plants are rich sources of oxygenated monoterpenes and sesquiterpenes. Among oxygenated monoterpenes, aromatic ether 2,5-dimethoxy-p-cymene is the most abundant and dominant compound of many essential oils of the Laggera species. Till today, to the best of our knowledge, chemical compounds of the essential oils and/or extracts of only eight Laggera species were reported from different countries. Thus, this review presents the chemical compositions and biological activities of the essential oils of these plants studied in thirteen countries. In addition, it discusses the reported ethnobotanical and ethnopharmacological information as well as biological activities of the extracts and some of the isolated compounds of Laggera plants species.