Analysis of the phytochemical contents and antioxidant activities of crude extracts from Tulbaghia species

OBJECTIVE: To assess the phytochemical contents and antioxidant activities of crude extracts from selected Tulbaghia species.METHODS: Standard methods were used for preliminary phytochemical analysis. The total phenolic acid contents of the plant extracts were determined using the Folin-Ciocalteu method, and the total flavonoid contents were determined using the aluminum chloride colorimetric method. 1,1-Diphenyl-2-picrylhydrazyl and 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assays were used to evaluate the antioxidant activities.RESULTS: Phytochemical screening showed flavonoids, glycosides, tannins, terpenoids, saponins,and steroids were present in the Tulbaghia species.The total phenolic acid and flavonoid contents varied in the different plant extracts, ranging from4.50 to 11.10 mg of gallic acid equivalents per gram of fresh material and 3.04 to 9.65 mg of quercetin equivalents per gram, respectively. The IC50 values determined for Tulbaghia alliacea and Tulbaghia violacea based on 1,1-diphenyl-2-picrylhydrazyl(0.06 and 0.08 mg/m L, respectively) and 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)(0.06 and 0.03 mg/m L, respectively) were low and showed they had potential antioxidant activities.CONCLUSION: Our results suggest that individual compounds from Tulbaghia species should be isolated for analysis of their antioxidant activity because some compounds may work best when pure.     

Analysis of the phytochemical contents and antioxidant activities of crude extracts from Tulbaghia species

OBJECTIVE

To assess the phytochemical contents and antioxidant activities of crude extracts from selected Tulbaghia species.

Ethical and legal constraints to children’s participation in research in Zimbabwe: experiences from the multicenter pediatric HIV ARROW trial

Background

Clinical trials involving children previously considered unethical are now considered essential because of the inherent physiological differences between children and adults. An integral part of research ethics is the informed consent, which for children is obtained by proxy from a consenting parent or guardian. The informed consent process is governed by international ethical codes that are interpreted in accordance with local laws and procedures raising the importance of contextualizing their implementation.

Findings

In Zimbabwe the parental informed consent document for children participating in clinical research is modeled along western laws of ethics and requires that the parent or legally authorized representative provide consent on behalf of a minor. This article highlights the experiences and lessons learnt by Zimbabwean researchers in obtaining informed consent from guardians of orphaned children participating in a collaborative HIV clinical trial involving the Medical Research Council, United Kingdom and four centers, three of which are in Uganda. Researchers were faced with a situation where caregivers of orphaned children were not permitted to provide informed consent for trial participation. The situation contrasted with general clinical practice where consent for procedures on orphans is obtained from their caregivers who are not legal guardians.

Conclusion

The challenges faced in obtaining informed consent for orphans in this clinical trial underscores the need for the Zimbabwe ethics committee to develop an ethical and legal framework for pediatric research that is based on international guidelines while taking into account the cultural context. The Medical Research Council of Zimbabwe has since started the process that is expected to involve critical stakeholders namely the community including children, ethicists, the legal fraternity and researchers.     

Ethical and legal constraints to children's participation in research in Zimbabwe: experiences from the multicenter pediatric HIV ARROW trial

ABSTRACT: BACKGROUND: Clinical trials involving children previously considered unethical are now considered a necessity because of the inherent physiological differences between children and adults. An integral part of research ethics is the informed consent, which for children is obtained by proxy from a consenting parent or guardian. The informed consent process is governed by international ethical codes that are interpreted in accordance with local laws and procedures raising the importance of contextualizing their implementation. DISCUSSION: The Zimbabwean parental informed consent document for children participating in clinical research is modeled along western laws of ethics and requires that the parent or legally authorized representative provide consent on behalf of a minor. This article highlights the experiences and lessons learnt by Zimbabwean researchers in interpreting and obtaining informed consent for orphaned children participating in a collaborative HIV clinical trial involving the Medical Research Council, United Kingdom and four centers, three of which are in Uganda. Researchers were faced with a situation where caregivers of orphaned children were not permitted to provide informed consent for trial participation if the Zimbabwean courts had not legally appointed them. The situation contrasted with general clinical practice where legal papers where not required for providing consent for surgical procedures for example. SUMMARY: Experiences gained from this clinical trial revealed that while there may be internationally established guidelines governing the process of obtaining informed consent for children participating in research, there may be need to be cognizant of the culture within which the research is taking place. This may call for the development of an ethico-legal framework that governs research-involving children in Zimbabwe that would facilitate their participation in clinical research, while ensuring that they are protected from exploitation. The Medical Research Council of Zimbabwe has since started developing that framework in a process that is expected to involve critical stakeholders namely the community including children, ethicists, the legal fraternity and researchers.