Toxicology of medicinal plants and combinations used in rural northern KwaZulu-Natal (South Africa) for the treatment of hypertension

Traditionally used polyherbals in a southern African therapeutic context

ETHNOPHARMACOLOGICAL RELEVANCE

In African traditional medicine, there are several plant species that are used in combination with either other plant species or non-plant derived combinations such as sugar and honey, salt and vinegar, milk, fat etc. This review examines the role of these combinations and postulates the scientific and therapeutic validation of such combinations.

AIM OF THE STUDY

This study reviewed the ethnopharmacological literature and documented the use of southern African plant combinations to find a scientific rationale for such combinations, and provide recommendations for future studies.

MATERIALS AND METHODS

Ethnobotanical books and online databases such as Scopus, ScienceDirect, PubMed and Google Scholar were used to find ethnobotanical studies within the southern African context that focus on the combinations of plants with other plants or various additional ingredients. The scientific literature was examined to determine if evidence was available to substantiate such combinations.

RESULTS

One hundred and eighty-seven medicinal plant (plant-to-plant) combinations that are used in the southern African traditional healing system were recorded. These plant combinations were used against infections of the gastrointestinal tract, respiratory tract, and skin as well other non-infectious diseases such as reproductive and psychiatric disorders. Respiratory infections were the most documented infections to be treated using plant combinations. The plant that was documented to be most commonly used in combination with other plants was Artemisia afra Jacq. ex Willd. While plant-plant combinations have drawn a marked interest, comparatively, plant-adjuvant (e.g. milk, sugar, honey, salt, vinegar, fats) combinations have attracted less research interest. Milk was reported as the most used additional ingredient in combination with medicinal plants. The combination of animal urine and dung with medicinal plants has been reported as a treatment for treat prostate infections, the human immunodeficiency virus (HIV). Other ingredients such as clay and flour were also documented, and these are often mixed with medicinal plants to treat fever, stomach ailments, sexually transmitted infections (STI) and skin conditions. Although combination therapy has been frequently reported in ethnobotanical records, over 90% of the combinations reviewed still need to be scientifically validated.

CONCLUSION

Scientific reports on the antimicrobial, anti-oxidant, anti-inflammatory and other pharmacological effects of these combinations may offer an understanding of traditional combination therapy. In addition, investigation into the mechanisms of action of these combinations are also recommended to supplement the findings. Nonetheless, the use of plant combinations is still an untapped research area in southern Africa and there is a need to validate the use of those documented combinations to obtain a better understanding of combined traditional medicinal plant use.

A Comparison of Methylphenidate (MPH) and Combined Methylphenidate with Crocus sativus (Saffron) in the Treatment of Children and Adolescents with ADHD: A Randomized, Double-blind, Parallel-Group, Clinical Trial

Background: Attention-deficit/hyperactivity disorder (ADHD) is characterized by behavioral and neurodevelopmental problems. It is estimated that 3 - 7% of children and adolescents suffer from this problem. Apart from synthetic drugs, other effective types of medication like herbal medicines are of great importance. Objectives: This study aimed to evaluate the effectiveness of methylphenidate (MPH) and its combination with Crocus sativus (saffron) in the treatment of children suffering from ADHD. Methods: The sample included 70 children aged between 6 and 16 years who had been diagnosed with ADHD. The patients were randomly assigned into two equal groups (n = 35 in each group). While both groups received 20 or 30 mg/d of MPH (20 and 30 mg/d for < 30 and > 30, respectively), one of them also received 20 or 30 mg/d of saffron in a capsule based on BMI (20 and 30 mg/d for < 30 and > 30, respectively). To collect data, parents and teachers completed Attention-Deficit/Hyperactivity Disorder Rating Scale-IV (ADHD-RS-IV). Also, for analyzing the data, the repeated measures analysis of variance (RMANOVA) was used. Results: The results of general linear model (GLM) repeated measures indicated that in both groups, the patients had less symptoms after eight weeks of treatment. However, after four weeks, the average score assigned by the parents and teachers in the MPH with saffron group was lower than the average total score in the MPH group (P < 0.05). Conclusions: Using MPH combined with saffron proved to be more effective in the treatment of patients suffering from ADHD compared to separate treatments. It seems that the duration of therapy can be reduced and the effectiveness be improved by prescribing proposed combined treatment.

Mutagenic potential of medicinal plants evaluated by the Ames Salmonella/microsome assay: A systematic review

The Ames test has become one of the most commonly used tests to assess the mutagenic potential of medicinal plants since they have several biological activities and thus have been used in traditional medicine and in the pharmaceutical industry as a source of raw materials. Accordingly, this review aims to report previous use of the Ames test to evaluate the mutagenic potential of medicinal plants. A database was constructed by curating literature identified by a search on the electronic databases Medline (via Pubmed), Science Direct, Scopus, and Web of Science from 1975 to April 2020, using the following terms: "genotoxicity tests" OR "mutagenicity tests" OR "Ames test" AND "medicinal plants." From the research, 239 articles were selected, including studies of 478 species distributed across 111 botanical families, with Fabaceae, Asteraceae and Lamiaceae being the most frequent. It was identified that 388 species were non-mutagenic. Of these, 21% (83/388) showed antimutagenic potential, most notable in the Lamiaceae family. The results also indicate that 18% (90/478) of the species were mutagenic, of which 54% were mutagenic in the presence and absence of S9. Strains TA98 and TA100 showed a sensitivity of 93% in detecting plant extracts with mutagenic potential. However, the reliability of many reviewed studies regarding the botanical extracts may be questioned due to technical issues, such as testing being performed only in the presence or absence of S9, use of maximum doses below 5 mg/plate and lack of information on the cytotoxicity of tested doses. These methodological aspects additionally demonstrated that a discussion about the doses used in research on mixtures, such as the ones assessed with botanical extracts and the most sensitive strains employed to detect the mutagenic potential, should be included in a possible update of the guidelines designed by the regulatory agencies.