Bacterial and heavy metal contamination in selected commonly sold herbal medicine in Blantyre, Malawi

Microbial and heavy metal contamination in herbal medicine: a prospective study in the central region of Saudi Arabia

INTRODUCTION

Herbal medicine is a medical system based on the utilization of plants or plant extracts for therapy. The continual increase in global consumption and the trade of herbal medicine has raised safety concerns in many regions. These concerns are mainly linked to microbial contamination, which could spread infections with multi-resistant bacteria in the community, and heavy metal contamination that may lead to cancers or internal organs' toxicity.

METHODS

This study was performed using an experimental design. A total of 47 samples, herbal medicine products sold in local stores in Qassim region, were used in the experiments. They were tested for bacterial contamination, alongside 32 samples for heavy metal analysis. Bacterial contamination was determined by the streak plate method and further processed to determine their antimicrobial susceptibility patterns using MicroScan WalkAway96 pulse; heavy metals were determined using a spectrometer instrument.

RESULTS

A total of 58 microorganisms were isolated. All samples were found to be contaminated with at least one organism except three samples. The majority of the isolated bacterial species were gram negative bacteria, such as Klebsiella spp., Pseudomonas spp. and E. coli., which could be of fecal origin and may lead to pneumonia, skin, or internal infections. Furthermore, most of the gram-positive bacteria were found to be multi-drug resistant. Moreover, for heavy metals, all samples had levels exceeding the regulatory limits.

CONCLUSION

This study demonstrated the presence of bacteria and heavy metals in samples of herbal medicines. Using these contaminated products may spread resistant infections, metal toxicities, or even cancers in the community.

Estimation of selected elemental impurities by inductively coupled plasma-mass spectroscopy (ICP-MS) in commercial and fresh fruit juices

The main objective of the study is the estimation of elemental impurities in selected packaged commercial fruit juices and fresh fruit juices available in Ahmedabad, Gujarat. Estimation of seventeen samples (9 commercial fruit juices and 8 fresh fruit juices) was carried out for elemental impurities which include lead, cadmium, arsenic, mercury, methyl mercury, nickel, chromium, tin, copper, and zinc. Inductively coupled plasma-mass spectroscopy (ICP-MS) with microwave-assisted sample digestion was used to determine the element content of samples. The ICP-MS method was confirmed for accuracy by performing validation with validation parameters such as linearity, precision, and accuracy. The method's trueness was confirmed with single-element standards. The results were compared with Food Safety and Standards Authority of India (FSSAI) standards. Arsenic, mercury, methyl mercury, tin, and copper were within permissible limits in all samples of fruit juices. The concentration of lead was found to exceed limits in 5 samples of commercial fruit juices which were 0.07, 0.13, 0.18, 0.21, and 0.38 mg/kg, respectively. The concentration of nickel was found to be above permissible limits in 5 samples (1.26, 1.72, 1.95, 3.24, and 4.07 mg/kg) of commercial fruit juices and 6 samples of fresh fruit juices (0.19. 0.21, 0.21, 0.42, 0.66, and 2.42 mg/kg). The concentration of chromium was found to be above permissible limits in 5 samples (3.13, 3.51, 4.29, 5.91, and 6.02 mg/kg) of commercial fruit juices and 6 samples of fresh fruit juices (0.80. 0.88, 0.98, 0.99, 1.16, and 8.95 mg/kg). Health risk assessment was performed for elemental impurities. Target hazard quotient and health risk index for elemental impurities were found to be less than 1 which is considered safe for consumers. Hazard index for elemental impurities was found to be more than 1 in two samples which can cause serious non-carcinogenic risk to consumers. Target carcinogenic risk was found within acceptable levels for all elemental impurities in all samples of fruit juices. Essential elements like copper and zinc are required by the human body for various body functions but heavy metals like lead, arsenic, and cadmium are highly toxic to human beings due to their adverse effects and it needs to be controlled. Lead poses a significant health risk to human health. It is essential to further monitor the levels of elemental impurities on a regular basis in commercial and fresh fruit juices.

Soaking beans for 12 h reduces split percent and cooking time regardless of type of water used for cooking

Beans are one of the most important cheap source of protein in developing countries. However, their utilisation in the diets of many people remains limited due to long cooking time, among others. Therefore, it is imperative to identify ways to enhance utilisation of beans. The aim of the current study was to assess the effects of soaking and cooking in different types of water (tap, borehole, acidulated- 1.0 percent citric acid and soda- 0.2 percent sodium bicarbonate) on cooking time (CT), split percentage (SP) and total soluble solids (TSS) in broth of different varieties of beans. Results show that soaking significantly reduced CT across eight varieties from an average CT of 109.5–84.6 min in tap water, 109.5–85.2 min in borehole water, 115.9–92.7 min in acidulated water and 82.0–51.2 min in soda water representing 22.7%, 22.1%, 20.0% and 37.6% reduction in CT, respectively. Soaking generally decreased SP and varietal differences were observed suggesting beans are less likely to break when soaking precede cooking. Although cooking in soda water significantly reduced CT, unfortunately, it increased SP. Acidulated water extended CT but reduced SP in almost all varieties. Soaking generally decreased TSS in broth from 7.0 to 6.7% in tap water, 6.1–5.8% in borehole water and 11.3–7.7% in soda water while it increased TSS in acidulated water from 18.2 to 20.6% across all the eight varieties which suggest reduction in leaching out of bean solids into cooking water which is consistent with reduced SP of soaked beans. While use of soda water reduced cooking time and therefore saved time and energy, its effect of increasing split percent may not be appealing to some consumers. This study has demonstrated that bean soaking significantly reduced cooking time and split percent and these can also be affected by type of cooking water.

Antibiotic-resistance in medically important bacteria isolated from commercial herbal medicines in Africa from 2000 to 2021: a systematic review and meta-analysis

Background

Antimicrobial resistance is swiftly increasing all over the world. In Africa, it manifests more in pathogenic bacteria in form of antibiotic resistance (ABR). On this continent, bacterial contamination of commonly used herbal medicine (HM) is on the increase, but information about antimicrobial resistance in these contaminants is limited due to fragmented studies. Here, we analyzed research that characterized ABR in pathogenic bacteria isolated from HM in Africa since 2000; to generate a comprehensive understanding of the drug-resistant bacterial contamination burden in this region.

Methods

The study was conducted according to standards of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). We searched for articles from 12 databases. These were: PubMed, Science Direct, Scifinder scholar, Google scholar, HerbMed, Medline, EMBASE, Cochrane Library, International Pharmaceutical Abstracts, Commonwealth Agricultural Bureau Abstracts, African Journal Online, and Biological Abstracts. Prevalence and ABR traits of bacterial isolates, Cochran’s Q test, and the I² statistic for heterogeneity were evaluated using MedCalcs software. A random-effects model was used to determine the pooled prevalence of ABR traits. The potential sources of heterogeneity were examined through sensitivity analysis, subgroup analysis, and meta-regression at a 95% level of significance.

Findings

Eighteen studies met our inclusion criteria. The pooled prevalence of bacterial resistance to at least one conventional drug was 86.51% (95% CI = 61.247–99.357%). The studies were highly heterogeneous (I² = 99.17%; p < 0.0001), with no evidence of publication bias. The most prevalent multidrug-resistant species was Escherichia coli (24.0%). The most highly resisted drug was Ceftazidime with a pooled prevalence of 95.10% (95% CI = 78.51–99.87%), while the drug-class was 3^rd generation cephalosporins; 91.64% (95% CI = 78.64–96.73%). None of the eligible studies tested isolates for Carbapenem resistance. Extended Spectrum β-lactamase genes were detected in 89 (37.2%) isolates, mostly Salmonella spp., Proteus vulgaris, and K. pneumonia. Resistance plasmids were found in 6 (5.8%) isolates; the heaviest plasmid weighed 23,130 Kilobases, and Proteus vulgaris harbored the majority (n = 5; 83.3%).

Conclusions

Herbal medicines in Africa harbor bacterial contaminants which are highly resistant to conventional medicines. This points to a potential treatment failure when these contaminants are involved in diseases causation. More research on this subject is recommended, to fill the evidence gaps and support the formation of collaborative quality control mechanisms for the herbal medicine industry in Africa.

Unpredictable adverse effects of herbal products

Herbal products are being increasingly used all over the world for preventive and therapeutic purposes because of the belief of their safety. They have become an important part of health care system in many countries since they can easily be purchased in the health food stores or online. However, the lack of sufficient study on their efficacy and toxicity, inadequate controls of their availability, reduce their safety. Unlike conventional drugs, herbal products are not regulated for purity and potency. Herbal products contain substances which can induce or inhibit enzymes that take part in drug metabolism. Therefore the concurrent use of drugs with some medicinal plants can cause serious adverse effects and can also decrease the efficacy of the therapy. Particularly, drugs with narrow therapeutic index and plants which can affect drug metabolizing enzymes when used together, may lead to unpredictable adverse reactions. Impurities, contaminants and adulterants found in the herbal products, are the most common malpractises in herbal raw-material trade. In this review the unpredictable adverse effects of herbal products due to their possible interactions with drugs and also due to the adulteration and contamination with prohibited chemicals will be discussed in detail.