Biologically Active Natural Products from Asia and Africa: A Selection of Topics

The present study evaluated biological and physical contamination in terms of microbes and toxic metal, respectively, in eight antidiabetic herbal medicines (ADHMs) from different markets in Dhaka City, Bangladesh. Coliform, E. coli, Salmonella spp. and Listeria spp. were absent in all ADHMs. However, aerobic bacterial count of all the samples of yeasts and molds in some samples fails to satisfy safe limits set by different regulatory standards. Among the nine metals [Copper (Cu), Zinc (Zn), Lead (Pb), Manganese (Mn), Chromium (Cr), Iron (Fe), Cadmium (Cd), Nickel (Ni), and Arsenic (As)] investigated, Cu, Zn, Pb, Cr, Ni content was in safe limit according to different pharmacopoeia and WHO guidelines. Among all the regulatory authorities, only the Health Sciences Authority (HSA), Singapore claims the Cd content is above the permissible limit in all the samples except ADHM-4. Chinese pharmacopoeia restricts the use of ADHM-1, ADHM-2 and ADHM-8 because of unacceptable arsenic (As) contamination. All the targeted antidiabetic herbal medicines (ADHMs) were found to retain an unacceptable level of Mn, ranging from 0.44±0.01 to 4.17±0.03 ppm. Metals contamination poses potential risks to human health and regulatory authorities not only should impose a restriction on the use of the medicines but also direct guidelines to keep the drugs safe.

In developing countries, an increase of diabetes became an alarming issue and recognized as the third leading fatal disorder among all syndromes. Bangladesh also has a large number of diabetic people in the world. In the present study, the quantification of major toxic metals and the assessment of their safety in the antidiabetic herbal preparations had been undertaken. In our investigation, a handful of samples collected randomly from different kiosks and herbal retail shops in Dhaka city, Bangladesh, were exposed to the X-ray fluorescence (XRF) technique. It was found that the average concentration of calcium was the highest (660.82mg/50gm) and arsenic was the lowest in concentrations (<0.01mg/50gm) in all anti-diabetic herbal preparations (ADHPs). Cu, Fe and Ni concentration above the safety limits and two samples containing Zn concentration above the safety limits were recommended by WHO and FAO as 3 ppm, 20 ppm, 1.63 ppm and 50 ppm for herbal drugs, respectively. Other toxic heavy metals like As, Pb and Co were found with a respective concentration of <0.01, <0.012 and <0.22 mg/50 gm, which were all within their safe consumption limit. Patients who take the herbal drugs can suffer from dizziness, nausea and vomiting, dermatitis, irritation of the upper respiratory tract, abdominal pain, diarrhea, joints pain, shock, and even liver damage due to the overdose of iron and zinc. Based on the present study, it can be clarified that the percentage of heavy metal concentrations in herbal drugs in Bangladesh is at risk. Regulatory agencies should come forward and take the necessary measures to ensure the safety of finished herbal preparations.

Female primary infertility is a major global challenge known to be influenced by dietary factors, including caffeine intake. Moderate caffeine intake has been proposed to have beneficial health effects while excessive caffeine intake may represent health risks, with the reproductive system being one of them. However, studies regarding the association between high caffeine intake and reduced female infertility are still inconclusive. This evidence-based case report was investigated to know whether daily high caffeine consumption is associated with female primary infertility indicated by time to pregnancy (TTP) and spontaneous abortion (SAB).

A structured literature search for cohort, case-control and meta-analysis was performed using Pubmed and Scopus database. Selected articles were appraised using appraisal tools from CEBM for meta-analysis, and NOS assessment tool for cohort and casecontrol studies.

Four articles (one meta-analysis, two cohort studies, and one case-control study) were selected based on predefined selection criteria. High caffeine intake was not associated with 12 months TTP based on all studies, except for one case-control study. Whereas, based on the meta-analysis of 27 studies that provided sufficient data on SAB, it was shown that increased caffeine consumption significantly increased the risk of SAB. However, studies that assessed SAB had significant heterogeneity.

In conclusion, based on studies with the highest evidence level and appropriate NOS and CEBM scores, we found an insignificant association, if any, between high caffeine intake and primary infertility based on two indicators, which were TTP and SAB. Therefore, we recommend that women trying to achieve pregnancy do not necessarily need to restrict their caffeine intake.

Urena genus consists of two species named Urena lobata L. and Urena sinuata L. These plants have various pharmacological properties, including antioxidant, anti-diarrheal, anti-parasitic, anti-inflammatory and analgesic activities and a variety of phytochemicals. U. sinuata is a medicinal herb, which is frequently used by the traditional practitioners in Bangladesh, India and many other countries of the world for the treatment of various diseases. The plant roots are anti-rheumatic, anti-pyretic, emollient, refrigerant, maturant, and act as a cooling agent. In this study, we summarize a detailed overview of the U. sinuata based on the most recent available literature (till Jun 2020). Findings suggest that U. sinuata possesses many important phytochemical and pharmacological activities. According to scientific reports, U. sinuata possesses carbohydrates and gums, reducing sugars, alkaloids, steroids, glycosides and flavonoids. Pharmacological investigations suggest that the plant has antioxidant, antidiarrheal, anti-inflammatory, anti-pyretic, anxiolytic, analgesic, sedative, thrombolytic, insecticidal and repellent activities. In conclusion, U. sinuata may be one of the best sources of plant-based drugs.

Background: Chikungunya (CHIKV) is a mosquito-borne viral disease first described during an outbreak in southern Tanzania in 1952. It is an RNA virus, belonging to the alphavirus genus of the family Togaviridae. To date, CHIKV has been identified in over 60 countries in Asia, Africa, Europe and the Americas. Diterpenes consist of two terpene units, often with the molecular formula C20H32, and have four isoprene subunits, often known for their diverse biological effects, including anti-bacterial, anti-fungal, and anti-viral effects. Scientific reports over the past few decades, suggest that diterpenes and their derivatives can be one of the potential sources of therapeutic tools for the management of infectious diseases.

Aim: This review covers an up-to-date (2011 to July 2019) information regarding the anti-CHIKV effects of diterpenes and their derivatives on the basis of scientific evidence observed in databases.

Materials and Methods: A search was done in databases: PubMed, ScienceDirect, and Google Scholar by using relevant keywords.

Results: Findings report 121 diterpenes and their derivatives acting against CHIKV; among them, 54 were found to inhibit strongly with the EC50 <10 μM; while 18, 10, 10, and the rest are with 10 to <20 μM, 20 to <50 μM, 50 to <100 μM, and >100 μM, respectively.

Conclusion: More researches are necessary to investigate their possible mechanism of action behind the anti-CHIKV effect. Of note, diterpenes may be one of the important sources of anti-CHIKV drugs.

Psoriasis is an anti-inflammatory condition associated with painful, itchy skin and typical skin lesions. Usually, psoriasis is characterized by the appearance of thick, red, scaly patches on the skin and build-up of dead skin cells leading to painful inflammation in the joints. Due to the lack of possible cure and the disadvantages of allopathic medicines, there is a need to develop new formulations from natural products having antipsoriatic activity. Argemone Mexicana Linn. acts as an anti-inflammatory drug for the treatment of psoriasis with no side effects as compared to synthetic drugs. Considering the anti-inflammatory activity, the attempt was made to develop a new herbal formulation for anti-inflammatory study. The developed formulations were subjected to physicochemical evaluation.

The transition from raw herbs to synthetic pharmaceuticals bioactive compounds has undergone evolution and herbal medicine has become an important source of raw materials to treat different illnesses. Indeed, the alternative treatment using herbal medicine has come into demand in recent years and has renewed interest in the plants that are effective, safe, and culturally acceptable. In Morocco, several medicinal plants are used traditionally to treat kidney stones and in vitro and in vivo experimental studies have proved their antilithiasic activity. This review aims to list all in vitro and in vivo antilithiasic medicinal plants used by the Moroccan population and to present bioactive compounds responsible for this activity. Further, we determined some molecular targets by these bioactive compounds.

Aristolochia longa is a medicinal plant used in traditional Mediterranean pharmacopeia to treat different diseases. It shows significant anti-inflammatory, antidiabetic, antioxidant, antibacterial, and antitumoral pharmacological effects. The extracts of this plant are rich in bioactive molecules belonging to different chemical families such as limonene, aristolochic acid, β-caryophyllene, and deenax. However, excessive use of this plant causes severe toxicity to the user. The aim of the present review is to give particular emphasis on the most recent findings on biological effects of the major groups of Aristolochia longa components, their therapeutic use, and the active ingredient responsible for the toxicity of this plant, which constitutes a public health problem observed with it’s wide use in cancer patients.

Stem bark, in combination with the leaves of Sphenocentrum jollyanum, is used for the management of wounds in the Southern part of Nigeria. The wound healing potential was determined by applying different concentrations of the prepared plant extracts, alone and in combination, to deep partial-thickness wounds on a rat model. Wound healing was measured on 15 days post-operation and compared with the controls. The percentage wound closure efficacy of the combined leaves and stem bark extracts were determined and compared statistically by 22 Factorial design model over 2, 8, and 15 post-operative days. Fluctuations in the wound surface pH were also measured over 15 days. All the extracts-treated wounds epithelized faster with dosedependent wound contraction, reaching statistically significant differences (p<0.01) compared with untreated wounds. The stem bark extract was about 50% more potent than the leaves extract. A significantly higher wound contraction effect of combined extracts was observed when compared with the individual extract effects. Also interesting was the <10 days complete epithelization observed in combined (200 mg equivalent) leaves and stem bark-treated wounds, which is shorter than 13 postoperative days in both 100 mg stem bark extract- and cicatrin-treated groups. However, there was no statistical evidence (*p<0.0) of interaction between the leaves and stem bark extracts; and improved activities of the combined extracts, in comparison with the individual extracts, were purely additive. The initial alkaline wound surface pH normalized to acidic pH within 8 and 12 post-operative days in extracts- and positive control-treated wounds. S. jollyanum extracts possess promising wound healing property. This study validated the primary folkloric use of the plant and aside from additive effect, empirical and statistical evidences showed that there was no basis for the claimed potency of combined leaves and stem as used by the traditional healers.