Sequential Extraction as Novel Approach to Compare 12 Medicinal Plants From Kenya Regarding Their Potential to Release Chromium, Manganese, Copper, and Zinc

Determination of Essential Minerals in the Indigenous Vegetables Solanum nigrum (Stout Shade) and Gynandropsis gynandra (Spider Plant) from Two Agroecological Zones in Kisii County, Kenya

Vegetables are good sources of essential mineral elements that promote good health and immunity. Information on the nutritional contents of indigenous vegetables is scarce. Therefore, this study sought to ascertain the concentrations of magnesium, manganese, chrome, zinc, copper, and iron in Solanum nigrum and Gynandropsis gynandra indigenous vegetables from two agroecological zones (upper midland and lower highland) of Kisii County, Kenya, using inductively coupled plasma optical emission spectroscopy (ICP‒OES). For Gnandropsis gynandra, the most abundant erythrocytic synthesis element was Fe (1856.67 ± 15.28 mg/kg DW) for plants harvested from Nyanchwa (UM), and the least was Cu (8.90 ± 0.44 mg/kg DW) in plants harvested from Kari (LH). In addition, Mg was the hypoglycemic element with the highest concentration (5975.00 ± 10.00 mg/kg DW), and Cr lowest (3.16 ± 0.45 mg/kg DW) in samples harvested from Matongo (UM). For Solanum nigrum, the most erythrocytic synthesis element was Fe (1280.00 ± 10.00 mg/kg DW for samples collected from Kiamabundu (UM), and the least was Cu (9.08 ± 0.15 mg/kg DW) in the samples from Nyanchwa (UM), whereas Mg in samples from Nyabioto (UM) was the hypoglycemic element with the highest concentration (4920.00 ± 10.00 mg/kg DW) and Cr in samples from Mariba (LH had the lowest concentration) (3.95 ± 1.63 mg/kg DW). The concentrations of elements in the two indigenous vegetables from the UM agroecological zone were slightly greater than those in the LH agroecological zone. Nonetheless, the variations observed were not statistically significant (P < 0.05). Enzymatically bio accessed concentrations of iron, zinc, chromium, magnesium, manganese, and copper were higher than those obtained aquatically. The indigenous vegetable bio avails substantial amounts of iron and copper to enable them be used in the management pernicious anaemia; on the other hand, the substantial bio availed levels of zinc, manganese, magnesium, and chromium enables the vegetable to be used in the management of diabetes.

Tannery waste-derived biochar as a carrier of micronutrients essential to plants

The leather tannery industry generates about 33 Mt/year of solid waste with different properties, turning its management into a challenge. One of the valorization methods of tannery wastes is the production of biochar by pyrolysis of leather scratches. Biochar's sorption properties and its high nitrogen content (10%) make it suitable for its application as a soil conditioner or carrier of microelements for fertilizers. The paper presents an innovative spray method to enrich biochar with cationic micronutrients: Cu, Mn, Zn. Enriched biochar contained 1095 mg/kg Cu(II), 1334 mg/kg Mn(II) and 1205 mg/kg Zn(II). The high bioavailability of nutrients and the effectiveness of the new fertilizer were demonstrated in extraction in vitro tests - the analysis of leachability of elements to water and bioavailability of micro-nutrients. The functional properties of enriched biochar were examined in vivo (germination, pot) tests. A high biomass increase (approximately 10%) was observed compared to the group fertilized with a commercial product. The proposed solution benefits the environment in that it is made from alternative resources from which innovative fertilizers are produced according to the circular economy concept.

Trace Elements in Medicinal Plants Traditionally Used in the Treatment of Diabetes-Do They Have a Role in the Claimed Therapeutic Effect?

Background: Medicinal plants are often used in the treatment of diabetes mellitus, although knowledge about their mode of action and the substances responsible for their antidiabetic potential is limited. It is well known that some trace elements play a role in glucose metabolism and insulin action. Thus, a particular trace elements profile could be associated with the antidiabetic properties observed for some medicinal plants. Methods: Infusions (n = 102) prepared from commercial herbal products (n = 34) containing medicinal plants indicated for the treatment of diabetes (n = 16 different plant species) and infusions (n = 60) prepared from commercial herbal products (n = 20) containing medicinal plants without such an indication (n = 7 different plant species) were analyzed by ICP-MS for their trace elements content. Results: In both groups, results varied significantly between different medicinal plants and also between different origins (brands) of the same medicinal plant. Significant differences (p < 0.05) between the two groups were found for nine elements, including four trace elements related to glucose metabolism (Mn, B, V, and Se), but with lower median contents in the group of medicinal plants for diabetes. Conclusions: Except for some particular species (e.g., Myrtilli folium) in which the trace element Mn may play a role in its antidiabetic effect, globally, a direct association between the claimed antidiabetic properties and a specific trace element profile of the studied medicinal plants was not evident.

Antiviral iridoid glycosides from Clerodendrum myricoides

The methanol root extract of Clerodendrum myricoides (Hochst.) Vatke afforded two new (1, 2) and two known (3, 4) iridoid glycosides. The structures of the isolated compounds were established based on NMR, IR, UV and MS data analyses. The crude extract and the isolated constituents were assayed for antiviral activity against the human respiratory syncytial virus (RSV) in human laryngeal epidermoid carcinoma (HEp-2) cells. The crude extract inhibited RSV infectivity at EC₅₀ = 0.21 μg/ml, while it showed cytotoxicity against HEp-2 cells with CC₅₀ = 9 μg/ml. Compound 2 showed 43.2% virus inhibition at 100 μM, while compounds 1 as well as 3 and 4 had only weak antiviral and cytotoxic activities.

Effect of Farm Additives on the Potential Bioavailability of Some Nutritional Elements from Kenyan Wild Plants

In this study, the effects of farm additives on eight wild plants from Nyamira County, Kenya were evaluated for their release of iron, copper, calcium, potassium and magnesium. A hundred and sixty traditional medicinal practitioners were surveyed and found to use Solanum indicum, Carissa edulis, Urtica dioica, Clerodendrum myricoides, Aloe vera, Plectranthus barbatus, Bidens pilosa and Solanum mauense. Atomic absorption spectrophotometer was used to determine the total nutritional element contents in the plants while ultra filtration and physiologically based extraction tests were used to determine the release and solubility of the nutritional elements. The plants from areas with high use of farm additives were found to have statistically significant high total levels of copper from the area with no or little application. Elemental analysis of the molecular species fractions into < 3 kDa, 3-10 kDa, 10 kDa-0.45 μm and 0.45-5 μm mass fractions showed that the mass distribution of the elements in the plants depended on the element. The nutritional elements released by gastrointestinal digestion were more than those released aquatically. Farm additives had no significant effect on the levels of most nutritional elements determined and the plants can be used as mineral element supplements in the human body in addition to their therapeutic activity.

Comparison of aqueous and enzymatic extraction combination with sequential filtration for the profiling of selected trace elements in medicinal plants from Kenya

This work presents results for the profiling of eight essential elements (Co, Cu, Ni, V, Mo, Mn, Zn and Cr) in aqueous and enzymatic extracts of eight anti-diabetic medicinal plants, used by Traditional Medicine Practitioners from Nyamira County, Kenya determined by ICP-MS. The plants used in the study were Solanum indicum, Plectranthus barbatus, Ultrica dioica, Bidens pilosa, Solanum mauense, Clerodendrum myricoides, Carissa edulis and Aloe vera. A sequential filtration procedure was applied to fractionate the elemental contents of the obtained aqueous extracts into molecular size fractions. The results indicate that the low molecular size species (<3 kDa) were predominant for Mo, Zn, Ni, Co, Mn and Cu, while the moderately large species (10 kDa-0.45 μm) of V were predominant in most of the medicinal plant extracts. In addition enzymatic extraction was compared to aqueous extraction to study the effect of the gastric and intestinal conditions on the release of selected elements from the plants. The amount of the elements extracted by the gastric phase enzymes was higher than the amount extracted by the intestinal phase enzymes. In general, the determined elemental amounts of enzymatic extractions were higher than those of corresponding water extractions for 70% of the elements studied.