Bioactive triterpenoids, antimicrobial, antioxidant and cytotoxic activities of Eclipta prostrata Linn.

Bioactive triterpenoids; 3-acetylaleuritolic acid, stigmasterol, a mixture of triterpenoids, fatty esters and aromatic components were isolated from the aerial parts of Eclipta prostrata by column chromatography. The plant extracts were investigated for their antimicrobial activity (agar dilution method) against twenty-eight strains of gram-positive and gram-negative bacteria, including diploid fungus. In addition, antioxidant and cytotoxic activities were also evaluated. The extracts and isolated fractions exhibited antimicrobial activity against Morexella catarrhalis, Corynebacterium diphtheriae NCTC 10356 and Streptococcus pyogenes with the MIC of 64 g/mL including Saccharomyces cerevisiae ATCC 2601 (MIC 256 g/mL). The ethyl acetate extract and isolated fractions displayed antioxidant effect. In addition, the plant extracts showed cytotoxic activity (ED50 > 100 g/mL) toward HuCCA-1 and KB cells. The results demonstrate beneficial effects of E. prostrata as the antimicrobials and bioactive compounds for medicinal usages.

Antimicrobial and cytotoxic acetogenin from Polyalthia debilis.

The objective of the study was to isolate bioactive acetogenin compound and to investigate antimicrobial, antioxidant as well as cytotoxic activities of the isolate, fractions and extracts of Polyalthia debilis. The P. debilis (roots) extracts and isolated compound were tested for their antimicrobial (agar dilution method) against twentyseven strains of microorganisms (gram positive and gram negative bacteria, and diploid fungus), antioxidant (DPPH assay) and cytotoxic activities. The plant extracts were isolated by column chromatography and structure of compound was confirmed by spectral data. The plant extracts and isolated fractions exhibited antioxidant and cytotoxic activities. The isolated acetogenin 1 (debilisone E) displayed antimicrobial activity against Morexella catarrhalis with the MIC of 64 g/mL, Corynebacterium diphtheriae NCTC 10356 and Streptococcus pyogenes with partial inhibition (50-75%) at 128 g/mL. The compound 1 exerted cytotoxic activity against 5 cancer cells (HepG2, A549, HCC-S102,HL-60 and P388) with IC50 values 18.4 - 40.3g/mL. The results demonstrate novel bioactivities of P. debilis as antimicrobials and anticancer agents.

A lyophilized formulation to extend the shelf-life of tuberculin PPD.

This study was aimed to develop a dry purified protein devirative (PPD) preparation to extend the shelf-life of tuberculin PPD. Five percent sucrose (S), 6.5% mannitol (M), 2.5% trehalose (T) or 0.3% Hemaccel (H) was added to each formulation. In vivo and in vitro analyses were carried out to determine the efficacy of the lyophilized products. In the in vivo test, the delayed type hypersensitivity (DTH) responses of the lyophilized preparations were compared to the liquid preparation (CL) after injection into BCG vaccinated guinea pigs. The preparations of H, M, T, and S generated DTH responses of 100, 90, 89, and 60%, as compared to the response of CL, respectively. There was no loss of tuberculin activity in the H formula. A statistically significant difference in activity was found between S and CL (p < 0.05). The cellular test for IFN-gamma secretions was performed using the whole blood of human subjects screened for DTH response to tuberculin PPD Mantoux tests. The detection of IFN-gamma secretions was done using ELISA and the efficacy was expressed in terms of percentage of IFN-gamma responses to the tuberculin antigens. The results of CL, H, M, T and S were 3.28, 10.40, 0.84, 1.52 and 1.29%, compared to mitogen stimulation, respectively. The lyophilized H, M and T formulations and the liquid CL were studied for their shelf-life stabiliy. Accelerated degradation was done by storing the samples at higher temperatures of 37 degrees C and 56 degrees C for 3, 6, 9 and 12 months. All the tuberculin PPD solutions were injected into BCG vaccinated guinea pigs at the end of each storage period and the activity of each solution was evaluated. The formulation with the Hemaccel as excipient gave a superior response than the others at the normal storage temperature of 40 micro C for 12 months. Therefore, Hemaccel provides protection for PPD activity. This supports the potential for the development of lyophilized tuberculin PPD with the addition of 0.3% Hemaccel to extend shelf life.

One-step purification of chimeric green fluorescent protein providing metal-binding avidity and protease recognition sequence.

Gene fusion technique was successfully applied as a potential approach to create a metal-binding site to assist one-step purification of green fluorescent protein (GFP). The chimeric GFP carrying hexapolyhistidine (H6GFPuv) was purified to homogeneous protein via the Immobilized Metal Affinity Chromatography charged with zinc ions. Removal of metal tagger could readily be performed by using enterokinase enzyme. Engineering of the hexahistidine and enterokinase cleavage sites (DDDDK) onto the chimeric protein did not significantly affect the fluorescent property and the binding avidity to Burkholderia pseudomallei protease of a chimeric protease-binding GFP (H6PBGFPuv). This concludes that engineering of repetitive histidine regions onto interested target protein along with the enterokinase cleavage sites will ease the complication of protein purification.