Antibacterial and antimycobacterial activities of South African Salvia species and isolated compounds from S. chamelaeagnea

Extracts of 16 South African Salvia species commonly used in traditional medicine to treat various microbial infections were investigated for in vitro antibacterial and antimycobacterial activities using the micro-dilution and respiratory BACTEC method, respectively. The micro-organisms tested include two Gram-positive (Staphylococcus aureus and Bacillus cereus); two Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacterial strains and the common pathogen responsible for tuberculosis, Mycobacterium tuberculosis. Extracts of the majority of species exhibited moderate to good antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.03 to 8.00 mg/ml. Promising activity was observed against M. tuberculosis (MIC ≤ 0.50 mg/ml) with S. radula, S. verbenaca and S. dolomitica displaying the most favourable activity (MIC: 0.10 mg/ml). The antibacterial bioassay-guided fractionation of S. chamelaeagnea resulted in the isolation of four compounds: carnosol, 7-O-methylepirosmanol, oleanolic acid and its isomer ursolic acid as the active principles against S. aureus. The in vitro antibacterial and antimycobacterial activities may support the use of Salvia species in traditional medicine to treat microbial infections

The role of flavor and fragrance chemicals in TRPA1 (transient receptor potential cation channel, member A1) activity associated with allergies

TRPA1 has been proposed to be associated with diverse sensory allergic reactions, including thermal (cold) nociception, hearing and allergic inflammatory conditions. Some naturally occurring compounds are known to activate TRPA1 by forming a Michael addition product with a cysteine residue of TRPA1 through covalent protein modification and, in consequence, to cause allergic reactions. The anti-allergic property of TRPA1 agonists may be due to the activation and subsequent desensitization of TRPA1 expressed in sensory neurons. In this review, naturally occurring TRPA1 antagonists, such as camphor, 1,8-cineole, menthol, borneol, fenchyl alcohol and 2-methylisoborneol, and TRPA1 agonists, including thymol, carvacrol, 1’S-1’- acetoxychavicol acetate, cinnamaldehyde, α-n-hexyl cinnamic aldehyde and thymoquinone as well as isothiocyanates and sulfides are discussed

VARIATION IN ESSENTIAL OIL COMPOSITION OF BOSWELLIA CARTERII BIRDW. AND ITS ANTIMICROBIAL ACTIVITY

Boswellia carterii (Burseraceae) is used in traditional medicine, the cosmetic industry and in aromatherapy in many countries all over the world. This plant produces the lucrative commercial oil known as Frankincense oil which has a woody, spicy and haunting smell. Frankincense oil has several pharmacological properties and these include the promotion of the growth of skin cells, healing sores and wounds. Variation in the chemical composition of this oil has been reported in the literature. This prompted an investigation to study the commercial Frankincense oils from various suppliers. Twenty essential oils were analyzed by gas chromatography coupled to mass spectrometry. Most of the oils were qualitatively similar when looking at the major components. However, there was some significant quantitative variation. The major components that were identified in the oils included á-pinene (2-64%), á-thujene (1-33%); â-pinene (0.3-13%); myrcene (1-9%); sabinene (2-7%); limonene (1-20%); p-cymene (3-17%); â-caryophyllene (0.1-8%). The antimicrobial activity of the oils was investigated on gram-positive (Staphylococcus aureus and Bacillus cereus) and gram-negative bacteria (Escherichia coli and Proteus vulgaris) as well as on a yeast (Candida albicans). Efficacy ranged between 1.5-32 mg/mL, depending on the test organisms studied. The highest sensitivity was observed against B. cereus