Evaluation of Potentially Toxic Metal Contamination of Local Medicinal Plants and Extracts Sold in Ibadan, Nigeria

New insights of the application of water or ethanol-water plant extract rich in active compounds in food

Plants are recognized as natural sources of antioxidants (e.g., polyphenols, flavonoids, vitamins, and other active compounds) that can be extracted by green solvents like water, ethanol, or their binary mixtures. Plant extracts are becoming more used as food additives in various food systems due to their antioxidant abilities. Their application in food increases the shelf life of products by preventing undesirable changes in nutritional and sensory properties, such as the formation off-flavors in lipid-rich food. This review summarizes the most recent literature about water or ethanol-water plant extracts used as flavors, colorings, and preservatives to fortify food and beverages. This study is performed with particular attention to describing the benefits of plant extract-fortified products such as meat, vegetable oils, biscuits, pastries, some beverages, yogurt, cheese, and other dairy products. Antioxidant-rich plant extracts can positively affect food safety by partially or fully replacing synthetic antioxidants, which have lately been linked to safety and health issues such as toxicological and carcinogenic consequences. On the other hand, the limitations and challenges of using the extract in food should be considered, like stability, level of purity, compatibility with matrix, price, sensory aspects like distinct taste, and others. In the future, continuous development and a tendency to use these natural extracts as food ingredients are expected, as indicated by the number of published works in this area, particularly in the past decade.

Morus alba fruit diet ameliorates cognitive deficit in mouse model of streptozotocin-induced memory impairment

Mounting evidence shows that dietary intake of fruits with polyphenols is beneficial to improve impaired memory functions. This study explored the preventive as well as therapeutic effects of diet enriched with Morus alba fruits extract (DEMA) in streptozotocin (STZ) induced mouse model of memory impairment. The study consisted of two facets: one aspect consisted of pretreatment of animals with DEMA for two weeks followed by STZ (i.c.v) intervention and the second phase involved induction of dementia with STZ (i.c.v) followed by treatment with DEMA for 14 days. Cognitive functions of animals were measured by Morris Water Maze test and to delineate the associated mechanism of action, brain biochemical estimations (acetyl-cholinesterase activity, myeloperoxidase activity, thiobarbituric acid reactive species, superoxide dismutase activity, reduced glutathione and nitrite/nitrate) and histopathological studies (haematoxylin and eosin staining) were performed. Pre- and post- treatment with DEMA significantly prevented and attenuated, respectively, the detrimental effects of STZ on mice brain. The results demonstrated that dietary modification, by incorporation of M. alba fruits, reduces the incidence and aids in treatment of memory disorder in mice by reducing central cholinergic activity, decreasing oxidative stress and preventing neurodegeneration.

Quality assessment of African herbal medicine: A systematic review and the way forward

BACKGROUND

In Africa, herbalism supplements allopathic medicine's efforts to ensure Universal Health Coverage attainment. This review was conducted to identify and to summarise current literature on methodological approaches used for quality control of herbal medicines in Africa, to evaluate the gaps associated with existing strategies within context of best practices, and make recommendations for future improvements.

METHODS

A systematic search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were screened and assessed for eligibility.

RESULTS

118 articles were included into the study. There was a high preference for impurity profiling tests (77%) indicating the prioritization for tests that guarantee safety despite the limited analytical resources available. Other classes of tests reported included identification tests (29%), physicochemical tests (18%), and content assays (12%). Although standard methods exist in preparing samples for impurity tests, different techniques were observed in different studies, and this could lead to differences in analytical outcomes. Content assays focused on single marker assessments, which may be inadequate to comprehensively assess the quality of products.

CONCLUSION

This review provides knowledge of existing strengths and challenges for herbal medicine quality assessments in Africa. For future it is recommended to implement more studies on contaminants (e.g. mycotoxins) and pharmaceutical adulterants. The use of chemometrics to develop analytical methods should be promoted. Also, stakeholders in the medicine quality industry in Africa need to effectively collaborate to establish a well co-ordinated and harmonized system to provide a sustainable framework for the GACP and GMP guided production and quality assurance of herbal medicines.

Correlative study of heavy metal content with biological importance of Solanum virginianum leaf extract

Background

Rapid urbanization and industrialization have greatly impacted the inherent soil composition. Heavy metals disposed in the environment by anthropogenic activities toxicate flora and ultimately affect the phytochemical profile of medicinal plants. We report here such an investigation of the heavy metal concentrations in the leaf extract of Solanum virginianum (S. virginianum). This work has been extended to observe the phytochemical constituents and antibacterial significance of leaf extracts in methanol and aqueous medium.

Methods

The metal concentration was analysed on ICE 3000 series atomic absorption spectrometer. The antibacterial assessment was carried by disc diffusion technique against three gram-negative (Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa) and one gram-positive (Staphylococcus aureus) bacteria.

Results

The content of Iron (Fe), Manganese (Mn), Zinc (Zn), and Lead (Pb) were 2.04, 0.47, 0.41, and 0.10 mg/L, respectively. Saponin and coumarin were present in both extracts. Various other phytochemicals like steroids, terpenoid, and flavonoid, were present only in the water extract, while tannin was present only on methanol extract. The methanol and aqueous extracts exhibited their highest inhibition on S. aureus with zones of inhibition of 12 mm and 14 mm, respectively.

Conclusion

The aqueous extract possessed more phytochemicals than the methanol extract, and the aqueous extract exhibited better antibacterial activity. The high Fe content in the leaf extract may suggest its use as an anaemic medicine. Other metal contents are under the WHO range.