Antimicrobial activity of Ocimum sanctum leaves extracts and oil

The aim of this study was to evaluate the antimicrobial effects of ethanol, Hexane and Chloroform leaf extracts of O. sanctum against pathogenic bacteria to determine their potentials as antibacterial agent. Ocimum sanctum Linn known as Holy Basil is an aromatic plant native to the tropics of Asia and Africa being medicinally important plant in the family Lamiaceae. The family Lamiaceae is one of the most exploited medicinal plant family worldwide not only as a source of medicinal plants but also with its valuable essential oils being used as spices and flavours for various food products. Leaves have petioles, and are ovate, up to 5 cm long, usually slightly toothed. Leaves were separated from the stem, washed in clear water and dried until they were adequately dry to be ground (dried for 7 days). Dried leaves were powdered separately in an electric grinder until a homogenous powder was obtained. Ethanolic, Hexane, Chloroform extract was prepared from the powder obtained using “cold extraction method. The activity of Tulsi extract against K. pneumonia & Staphylococcus aureus was found to be higher at a concentration of 100% followed by 75% & 50% respectively. The maximum zone of inhibition was found to be 21&11mm against Kleibsiella pneumonia and 18&15mm against Staphylococcus aureus. The antimicrobial efficacy of Ocimum sanctum leaves indicates that the plant possesses potent antimicrobial properties as well as Ocimum is widespread in India, it can be recommended as an easily available and renewal source of antimicrobial agent instead of synthetic chemicals. Keywords:  Ocimum santum, Staphylococcus aureus, Klebsialla pneumonia, Disc Diffusion

The endocrine system and ageing

Complex changes occur within the endocrine system of ageing individuals. This article explores the changes that occur in the metabolism and production of various hormones and discusses the resulting clinical consequences. As individuals age there is a decline in the peripheral levels of oestrogen and testosterone, with an increase in luteinizing hormone, follicle-stimulating hormone and sex hormone-binding globulin. Additionally there is a decline in serum concentrations of growth hormone, insulin-like growth factor-I and dehydroepiandrosterone and its sulphate-bound form. Even though there are complex changes within the hypothalmo-pituitary-adrenal/thyroid axis, there is minimal change in adrenal and thyroid function with ageing. The clinical significance of these deficiencies with age are variable and include reduced protein synthesis, decrease in lean body mass and bone mass, increased fat mass, insulin resistance, higher cardiovascular disease risk, increase in vasomotor symptoms, fatigue, depression, anaemia, poor libido, erectile deficiency and a decline in immune function. For each endocrine system, studies have been carried out in an attempt to reverse the effects of ageing by altering the serum hormonal levels of older individuals. However, the real benefits of hormonal treatment in older individuals are still being evaluated.

5-Hydroxytryptamine induced excitation and inhibition in the subthalamic nucleus: action at 5-HT(2C), 5-HT(4) and 5-HT(1A) receptors

Extracellular single-unit recordings in mouse brain slices were used to determine the effect of exogenously applied 5-HT on STN neurones. Recordings were made from 74 STN cells which fired action potentials at a regular rate of 7.19+/-0.5 Hz. In 61 cells (82%), 5-HT application increased STN neurone firing rate (10 microM, 180+/-16.8%, n=35) with an estimated EC(50) of 5.4 microM. The non-specific 5-HT(2) receptor agonist alpha-methyl 5-HT (1-10 microM) mimicked 5-HT induced excitations (15 cells). These excitations were significantly reduced by pre-perfusion with the specific 5-HT(2C) receptor antagonist RS102221 (500 nM, 9 cells) and the 5HT(4) antagonist GR113808 (500 nM, 7 cells). In 6 cells (8%) 5-HT induced biphasic responses where excitation was followed by inhibition, while in 7 cells (9%) inhibition of firing rate was observed alone. Inhibitory responses were reduced by the 5-HT(1A) antagonist WAY100135 (1 microM, 4 cells). No inhibitory responses were observed following alpha-methyl 5-HT applications. Both the excitations and inhibitions were unaffected by picrotoxin (50 microM, n=5) and CNQX (10 microM, n=5) indicative of direct postsynaptic effects. Thus, in STN neurones, 5-HT elicits two distinct effects, at times on the same neurone, the first being an excitation which is mediated by 5-HT(2C) and 5-HT(4) receptors and the second an inhibition which is mediated by 5-HT(1A) receptors.