Comparative study of in-vitro antimicrobial activity and phytochemical composition of Sida cuneifolia fruits, leaves, and stem bark extracts

Background: Sida cuneifolia plant parts are important in ethno-veterinary medicine, but no studies exist on a comparative evaluation of phytochemical composition and antimicrobial properties of fruits, stem bark and leaves. This study evaluated and compared extraction yields, phytochemical composition as well as antibacterial and antifungal properties of ether, methanol and aqueous crude extracts of fruits, leaves, and stem bark of S. cuneifolia.Methods: Yields of extracts were determined, and qualitative phytochemical screening tests were carried out to establish their composition. Crude extracts were screened against five bacteria and two fungi. Agar disk diffusion technique was used to determine the inhibition zone diameters. Broth micro-dilution method was used to determine the minimum inhibition concentrations (MIC) and minimum bactericidal concentrations (MBC).Results: Triterpene aglycones, sterols, tannins, athracene derivatives, polyuronides and glucides were found in intense mounts in S. cuneifolia fruits. Leaves contained intense amounts of carotenoids, tannins, polyuronides and coumarin derivatives. For the leaves, methanol extracts had MICs and MBCs as low as (≤3.13 mg/ml) against the majority (6/7) microorganisms hence had the best activity. Considering the stem bark, the ether extracts had the best antimicrobial activity with MICs as low as ≤3.13 mg/ml against 6/7 microorganisms. For the fruits, the ether extracts had the best antibacterial activity with MICs and MBCs as low as (≤3.13 mg/ml) against all tested bacteria.Conclusion: The study provides scientific evidence for ethno-veterinary use of S. cuneifolia leaves, fruits and stem bark, and this can be exploited in the transformative development of ethno-medicine

Quantification of Lycopene from Tomatoes and Watermelons by Using Beer-Lambert Principle

Red tomatoes and red-fleshed watermelons contain a high level of lycopene.  It is well known that lycopene is precursor to vitamin A. In Uganda, and East Africa in general, there are so many tomato and watermelon varieties with little information on their lycopene content. However, no study has been done to estimate the quantity of lycopene in fresh tomatoes and watermelons in Uganda. The objective of this study was to quantify lycopene by using Beer-Lambert Principle. The varieties were bought from Nakulabye market in Kampala, and extracted by using solvent system of acetone/ethanol/ hexane (5ml/5ml/10ml). Stirring on ice was done for 15 minutes. 3 ml of deionized water was added after shaking. Samples were shaken for 5 minutes on ice and then left at room temperature for 5 minutes to allow the separation of phases. The lycopene layer were then separated and scanned in UV-VIS spectrophotometer. The results showed that the lycopene concentration ranged from 27 μg/g to 115 μg/g with % relative error ranged from 2.86 to 3.14, the standard error ranged from ± 0.013to ± 0.015,and standard deviation ranged from 7.38 to 29.5.  Both watermelons and tomato varieties contain the appreciable quantities of lycopene which is the significant nutrient for human body in daily life.

ETHNOBOTANICAL USES OF LANTANA TRIFOLIA L. AND SIDA CUNEIFOLIA ROXB. IN MUKUNGWE AND WABINYONYI SUB-COUNTIES OF CENTRAL UGANDA

Aim: This was an ethnobotanical study that was carried out to establish the traditional uses of Lantana trifolia L. and Sida cuneifolia Roxb. plants in selected parts of Central Uganda. Methods: The ethnobotanical study was done in August and September, 2012 in Mukungwe and Wabinyonyi sub-counties in Masaka and Nakasongola Districts respectively located in Central Uganda. Study sites and respondents were purposefully selected and information was obtained through semi-structured interview guides, key informant interview guides as well as observations. Eighty respondents were considered for semi-structured interviews and 15 for key informant interviews. Results: Seven ethnobotanical uses for Lantana trifolia were cited by respondents and majority (46.25%) of them used it as a herbal remedy. As a herbal remedy, Lantana trifolia managed 13 human disease conditions and mainly used in the management of cough and common colds by 22.5% of the respondents. Four ethnobotanical uses were cited for Sida cuneifolia and majority of the respondents (62.5%) used it as a herbal remedy as well as sweeping brooms. As a herbal remedy, Sida cuneifolia was reported to be useful in management of 12 disease conditions, fractures and sprains (bone setting) being mentioned by the majority of the of respondents (36.25 %). Conclusion: In conclusion, Lantana trifolia and Sida cuneifolia were culturally important ethnomedicines. Scientific validation of traditional claims as well as conservation of these plants should be encouraged in order to preserve and promote their use. [J Intercult Ethnopharmacol 2013; 2(3.000): 155-164

Synthesis of cyclic carbonates from epoxides and carbon dioxide catalyzed by talc and other phyllosilicates

Naturally occurring phyllosilicate minerals such as talc and vermiculite in conjunction with n-tetra butyl ammonium bromide (TBAB) co-catalyst were found to be efficient in the coupling of CO2 with epoxides to form cyclic carbonates. The reaction was carried out in a pressurized autoclave reactor at moderate pressures of 10–35 bars and temperatures of 100–150 °C. The optimized catalyst system exhibited > 90% conversion of the epoxides and > 90% selectivity for the desired cyclic carbonates, in the presence or absence of a solvent. The selectivity of the catalytic system could be improved with heat pre-treatment of the phyllosilicates albeit this resulted in slightly lower epoxide conversion. The results obtained using the heat treated phyllosilicates strongly support the hydrogen bond assisted mechanism for the cycloaddition of epoxides and CO2. The cycloaddition reaction could also be carried out in the absence of TBAB, although lower cyclic carbonate yields were observed. The phyllosilicate part of the catalyst system is heterogeneous, easy to separate after completion of reactions and reusable a number of runs without loss of activity

Advances in carbon dioxide and propylene oxide copolymerization to form poly(propylene carbonate) over heterogeneous catalysts

Chemical conversion of carbon dioxide (CO2) into value-added products is an attractive industrial process because it offers several economic and environmental advantages. This review presents advances and challenges in the CO2 and propylene oxide (PO) co-polymerization using heterogeneous catalysts to form poly (propylene carbonate) (PPC), an environmentally friendly polymer with several applications. In the co-polymerization process, CO2 is employed as a green carbon source, an alternative to the toxic phosgene which has numerous negative environmental impacts. However, this route of polycarbonate production, is hindered by the chemical inertness of CO2, and to overcome this, various catalysts have been developed. A number of heterogeneous catalysts including carboxylates, double metal cyanides and composites, have achieved varying success in activating CO2 in the production of polycarbonates. The effect of different reaction conditions including pressure, temperature and solvent has been explored. The limitations faced by various heterogeneous catalysts and improvements made over the past decades have been highlighted. Mechanistic insights for the production of PPC from CO2 and PO have been presented and the differences in both the regioselectivity and stereochemistry of the resultant polymers discussed