Wound healing activities and potential of selected african medicinal plants and their synthesized biogenic nanoparticles

In Africa, medicinal plants have been traditionally used as a source of medicine for centuries. To date, African medicinal plants continue to play a significant role in the treatment of wounds. Chronic wounds are associated with severe healthcare and socio-economic burdens despite the use of conventional therapies. Emergence of novel wound healing strategies using medicinal plants in conjunction with nanotechnology has the potential to develop efficacious wound healing therapeutics with enhanced wound repair mechanisms. This review identified African medicinal plants and biogenic nanoparticles used to promote wound healing through various mechanisms including improved wound contraction and epithelialization as well as antibacterial, antioxidant and anti-inflammatory activities. To achieve this, electronic databases such as PubMed, Scifinder® and Google Scholar were used to search for medicinal plants used by the African populace that were scientifically evaluated for their wound healing activities in both in vitro and in vivo models from 2004 to 2021. Additionally, data on the wound healing mechanisms of biogenic nanoparticles synthesized using African medicinal plants is included herein. The continued scientific evaluation of wound healing African medicinal plants and the development of novel nanomaterials using these plants is imperative in a bid to alleviate the detrimental effects of chronic wounds

In vitro Antidiabetic and Antioxidant effects of different extracts of Catharanthus roseus and its indole alkaloid, vindoline

The Catharanthus roseus plant has been used traditionally to treat diabetes mellitus. Scientific evidence supporting the antidiabetic effects of this plant’s active ingredient-vindoline has not been fully evaluated. In this study, extracts of C. roseus and vindoline were tested for antioxidant activities, alpha amylase and alpha glucosidase inhibitory activities and insulin secretory effects in pancreatic RIN-5F cell line cultured in the absence of glucose, at low and high glucose concentrations. The methanolic extract of the plant showed the highest antioxidant activities in addition to the high total polyphenolic content (p < 0.05). The HPLC results exhibited increased concentration of vindoline in the dichloromethane and the ethylacetate extracts. Vindoline showed noticeable antioxidant activity when compared to ascorbic acid at p < 0.05 and significantly improved the in vitro insulin secretion. The intracellular reactive oxygen species formation in glucotoxicity-induced cells was significantly reduced following treatment with vindoline, methanolic and the dichloromethane extracts when compared to the high glucose untreated control (p < 0.05)

The biochemical effects of Hypoxis hemerocallidea in the kidney and liver of streptozotocin-induced diabetic male Wistar rats

Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2015.Diabetes mellitus (DM) is an endocrine disorder that is characterised not only by severe hyperglycemia but also altered metabolism of glucose and lipids. It is a major health problem worldwide and its impact is greatly noticed in developing countries due to the lack of adequate medical facilities. Oxidative stress remains the principal factor that actively plays major roles in the onset and progression of diabetes mellitus and its complications. The use of medicinal plants in the treatment of DM has undisputedly gained the attention and interest of researchers throughout the globe mainly because plants have established promising outcomes in the treatment of diabetes. It is evident that the plants’ constituents possess therapeutically potent metabolites that have beneficial effects such as antioxidant, antidiabetic, anticancer, anti-inflammatory and antibacterial activities. Hypoxis hemerocallidea is a native plant that grows in the Southern African regions. H. hemerocallidea is well known for its beneficial medicinal values. In South Africa it is known as the African potato. The main aim of this study was to investigate both the beneficial and also the possible toxic effects of H. hemerocallidea in the kidney and liver tissues of streptozotocin-induced diabetic male Wistar rats by assessing the antioxidant status and selected biochemical parameters in the two studied organs. Diabetes was induced in overnight fasted rats by administration of a single intraperitoneal injection of STZ at a dosage of 50mg/kg in citrate buffer (0.1 M at 4.5 pH). Hyperglycemia was confirmed 72 hours after induction of diabetes using STZ in rats with glucose levels > 15 mmol/l. Treatment with the plants extract commenced on the fourth day after STZ administration via gastric gavage that was done once a day over a 6 week period. The effects of H. hemerocallidea on glucose, body weight, liver and kidney weights, liver function, kidney function and the oxidative status were evaluated after the feeding period

Modulatory and antidiabetic effects of vindoline and Catharanthus roseus in type 2 diabetes mellitus induced male Wistar rats and in RIN-5F cell line

Thesis (DPhil (Biomedical Science))--Cape Peninsula University of Technology, 2019.Diabetes mellitus (DM) is a group of metabolic disorders characterised by persistent high blood glucose levels together with abnormal metabolism of macromolecules. If the hyperglycemia is not controlled, adverse metabolic changes could occur leading to the progressive development of severe complications. Formation of reactive oxygen/nitrogen species and inflammatory responses are principal mechanisms that have been implicated in the development of hyperglycemia-induced tissue damage. The commercially available drugs utilised in the treatment of diabetes have been linked to detrimental side effects hence the need to discover alternative medicines especially from medicinal plants. Catharanthus roseus is both a medicinal and ornamental plant that is traditionally used to treat various diseases. It has been reported to possess antidiabetic, anticancer, antimicrobial and antioxidant properties. The plant has been shown to possess more than 100 monotepernoid indole alkaloids which were linked to the plants’ antihyperglycemic and antioxidant effects. Therefore, this study was carried out to investigate the effect of vindoline; a bioactive compound derived from C. roseus against type 2 diabetes–induced complications. The study also investigated the effects of Catharanthus roseus extracts in RIN-5F cell line. The study was carried out in two parts: viz in vitro and the in vivo assessments. The in vitro study initially investigated the polyphenolic content and antioxidant activities of vindoline and the 3 extracts (methanolic, aqueous and the dichloromethane) of C.roseus. The assays used to evaluate the antioxidant capacity of the extracts include oxygen radical absorbance capacity (ORAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibitory assay. Among the evaluated extracts, the methanolic extract demonstrated both high total polyphenolic content and antioxidant capacity. The HLPC analysis of the extracts was performed and showed highest concentrations of vindoline in the dichloromethane extract and the aqueous extract exhibited the least. The antioxidant activities of vindoline were determined and compared to a known antioxidant, ascorbic acid. Vindoline revealed stronger ORAC activity than ascorbic acid however the ferric reducing antioxidant power did not show any significant differences (p < 0.05). Insulin secretion studies were performed in a β-cell insulinoma cell line- RIN-5F exposed to different concentrations of glucose (high, low and in the absence of glucose). The studies were carried out to compare the β-cell stimulatory effect of vindoline to the extracts. After performing cytotoxic experiments, concentrations that resulted in about 80% cell viability were used to determine the insulin secretory effects. In cells that exposed to glucotoxicity (50 mM glucose), vindoline showed the highest β-cell stimulatory effect (p < 0.05) when compared to the untreated controls and to the cells that were treated with the methanolic extract. In cells that were exposed to a low glucose concentration, vindoline additionally showed significant β-cell stimulatory effect at p < 0.05 when compared to the aqueous and the methanolic extracts. Thereafter, the intracellular reactive oxygen species assay (ROSA) was performed in glucotoxicity-induced cells after treatment with vindoline and the respective extracts. The results were compared to the untreated control: vindoline, methanolic and the dichloromethane extracts indicated significant reduction in ROS generation (p < 0.05). Further measurement of the release of TNF-α, a pro-inflammatory cytokine in the cells following treatment, the results were not significant among the groups at p < 0.05. The carbohydrate enzymes inhibitory activity of vindoline and extracts of C.roseus (50, 25, 12.5 and 6.125 mg/ml) were measured. The alpha glucosidase inhibitory activities of the extracts at 50 mg/ml resulted in < 30% enzyme inhibition with no significant differences among the groups at p < 0.05. At lower concentrations, the dichloromethane extract exhibited significantly lower inhibitory activities when compared to the methanolic and the aqueous extract (p < 0.05). The alpha amylase inhibitory activity of the methanolic extract was significantly increased at all concentrations; recording the highest enzyme inhibition of approximately 40% (p < 0.5). However, the dichloromethane extract did not show any enzyme inhibitory activity. The enzyme inhibitory activity of vindoline was compared to acarbose-a known standard drug, for both enzymes; vindoline did not show appreciable enzyme inhibition when compared to acarbose (p < 0.05). In vivo studies were performed in a type 2 diabetes (T2DM) rat model in which T2DM was induced in 6 weeks old male Wistar rats by having them drink 10% fructose solution ad libitum for 14 days followed by a single intraperitoneal injection of streptozotocin (STZ 40 mg/kg) in freshly prepared 0.1 M citrate buffer (pH 4.5). Animals were randomly divided into six groups (n=8) and received daily treatments for 6 weeks with the vehicle, vindoline (20 mg/kg) or glibenclamide (5 mg/kg) via oral gavage. The effects of the treatments on blood glucose, insulin, body weight, organ weight, serum biochemical parameters, oxidative status, inflammatory markers and tissue histology were assessed in diabetic and non-diabetic rats. Administration of vindoline significantly (p < 0.05) reduced the fasting blood glucose in diabetic rats by 15% and significantly increased serum insulin levels when compared to the diabetic controls. Vindoline and glibenclamide significantly (p < 0.05) reduced the levels of circulating hepatic enzymes in T2DM; the results were significant when compared to the diabetic controls. Treatment with vindoline significantly improved the hepatic antioxidant status as indicated by increased ORAC, superoxide dismutase and catalase activities, indicative of the protective effect of vindoline in diabetes-induced hepatic injury. Assessment of the levels of pro-inflammatory cytokines in the hepatic tissue indicated remarkable reduction of TNF-ɑ by (-41%) and IL-6 (-28%) in diabetic rats treated with vindoline when compared to the diabetic controls (p < 0.05). The serum lipid profile showed marked increases in the levels of serum lipids (triglycerides, low density lipoproteins, total cholesterol and very low density lipoproteins) in diabetic controls when compared to all treatment groups (p < 0.05). Therefore, vindoline and glibenclamide showed possible protective effects against diabetes-induced cardiovascular disease. Kidney function assessment revealed increased levels of urea and creatinine in the diabetic control group. Vindoline and glibenclamide significantly reduced the urea and creatinine levels in diabetic rats. Vindoline additionally improved the FRAP in diabetic hearts. The SOD activity and ORAC were increased while lipid peroxidation was reduced in the kidneys of diabetic rats treated with vindoline when compared to the diabetic control (p < 0.05). Histopathological assessment in diabetic rats showed severe damage of the liver, kidney and pancreas. Treatment of diabetic rats with vindoline restored the structure of these organs which was indicated by minimum structural changes. The expression of pro-apoptotic marker caspase 9 in response to glucose stress was significantly higher in the diabetic control group when compared to all the treatment groups. Treatment with vindoline showed remarkable reduction of caspase 9 expression in the diabetic rats. In conclusion, persistent high blood glucose levels resulted in free radical induced tissue damage in the type 2 diabetes rat model. Vindoline demonstrated protective effects against diabetes induced hepatic, cardiac, pancreatic and nephritic injuries. In addition, vindoline improved insulin secretion in both in vitro and in vivo setups hence the findings suggest that vindoline could be an important agent that can be considered in the treatment and management of diabetes and diabetic complications

Hypoxis hemerocallidea significantly reduced hyperglycaemia and hyperglycaemic-induced oxidative stress in the liver and kidney tissues of streptozotocin-induced diabetic male wistar rats.

Background. Hypoxis hemerocallidea is a native plant that grows in the Southern African regions and is well known for its beneficial medicinal effects in the treatment of diabetes, cancer, and high blood pressure. Aim. This study evaluated the effects of Hypoxis hemerocallidea on oxidative stress biomarkers, hepatic injury, and other selected biomarkers in the liver and kidneys of healthy nondiabetic and streptozotocin- (STZ-) induced diabetic male Wistar rats. Materials and Methods. Rats were injected intraperitoneally with 50 mg/kg of STZ to induce diabetes. The plant extract-Hypoxis hemerocallidea (200 mg/kg or 800 mg/kg) aqueous solution was administered (daily) orally for 6 weeks. Antioxidant activities were analysed using a Multiskan Spectrum plate reader while other serum biomarkers were measured using the RANDOX chemistry analyser. Results. Both dosages (200 mg/kg and 800 mg/kg) of Hypoxis hemerocallidea significantly reduced the blood glucose levels in STZ-induced diabetic groups. Activities of liver enzymes were increased in the diabetic control and in the diabetic group treated with 800 mg/kg, whereas the 200 mg/kg dosage ameliorated hepatic injury. In the hepatic tissue, the oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP), catalase, and total glutathione were reduced in the diabetic control group. However treatment with both doses improved the antioxidant status. The FRAP and the catalase activities in the kidney were elevated in the STZ-induced diabetic group treated with 800 mg/kg of the extract possibly due to compensatory responses. Conclusion. Hypoxis hemerocallidea demonstrated antihyperglycemic and antioxidant effects especially in the liver tissue

Diabetes mellitus: economic and health burden, treatment and the therapeutical effects of Hypoxis hemerrocallidea plant

Diabetes mellitus (DM) is becoming one of the leading causes of death worldwide because of its adverse complications that include cardiovascular related diseases and chronic kidney disease. DM is considered a menace to public health due to the unavailability of adequate drugs to manage this condition, especially in poor developing countries such as those in the African continent. Proper management and treatment of this is lacking, which possibly explains escalating percentages of morbidity and mortality associated with it. In Africa, as a result of poor socio-economic conditions, it is nearly impossible to properly monitor and manage DM. Globally, the commercially available drugs used in diabetes treatment regimens have been associated with drastic side effects and are also mostly unaffordable in some developing countries (particularly in Africa), hence the need to investigate cheap and readily available medicinal plants such as Hypoxis hemerocallidea. It is important to thoroughly investigate the activities of medicinal plants in animal models to identify both their therapeutic and toxic effects. This review paper examines the potential anti-diabetic benefits of Hypoxis hemerocallidea based on experimental studies done on this plant between the years 2000 and 2016. The authors recommend that further studies on the different extracts of the plant be undertaken to discover the exact mechanisms of their actio

Wound Healing Activities and Potential of Selected African Medicinal Plants and Their Synthesized Biogenic Nanoparticles

In Africa, medicinal plants have been traditionally used as a source of medicine for centuries. To date, African medicinal plants continue to play a significant role in the treatment of wounds. Chronic wounds are associated with severe healthcare and socio-economic burdens despite the use of conventional therapies. Emergence of novel wound healing strategies using medicinal plants in conjunction with nanotechnology has the potential to develop efficacious wound healing therapeutics with enhanced wound repair mechanisms. This review identified African medicinal plants and biogenic nanoparticles used to promote wound healing through various mechanisms including improved wound contraction and epithelialization as well as antibacterial, antioxidant and anti-inflammatory activities. To achieve this, electronic databases such as PubMed, Scifinder&reg; and Google Scholar were used to search for medicinal plants used by the African populace that were scientifically evaluated for their wound healing activities in both in vitro and in vivo models from 2004 to 2021. Additionally, data on the wound healing mechanisms of biogenic nanoparticles synthesized using African medicinal plants is included herein. The continued scientific evaluation of wound healing African medicinal plants and the development of novel nanomaterials using these plants is imperative in a bid to alleviate the detrimental effects of chronic wounds

Co-Treatment of Caco-2 Cells with Doxorubicin and Gold Nanoparticles Produced from Cyclopia intermedia Extracts or Mangiferin Enhances Drug Effects

Mangiferin (MGF) is a natural and valuable polyphenol found in significant levels in many plant species, including Cyclopia intermedia (C. intermedia). In a previous study, we synthesized gold nanoparticles (AuNPs) using MGF and a water extract of C. intermedia and reported that these AuNPs have very low cytotoxicity toward a human colon cancer (Caco-2) cell line. Although the study also showed that these biogenic AuNPs in combination with doxorubic (DOX) significantly augmented the cytotoxic effects of DOX in Caco-2 cells, the mechanism of the enhanced effect was not fully understood, and it was also not known if other cell lines would be sensitive to this co-treatment. In the present study, we examined the cytotoxicity of the co-treatment in Caski, HeLa, HT-29, KMST-6 and MDA-321 cell lines. Additionally, we investigated the mechanistic effects of this co-treatment in Caco-2 cells using several assays, including the adenosine triphosphate (ATP), the oxidative stress, the mitochondrial depolarization, the colony formation, the APOPercentage and the DNA fragmentation assays. We also assessed the intracellular uptake of the biogenic AuNPs. The study showed that the biogenic AuNPs were effectively taken up by the cancer cells, which, in turn, may have enhanced the sensitivity of Caco-2 cells to DOX. Moreover, the combination of the biogenic AuNPs and DOX caused a rapid depletion of ATP levels, increased mitochondrial depolarization, induced apoptosis, reduced the production of reactive oxygen species (ROS) and inhibited the long-term survival of Caco-2 cells. Although the study provided some insight into the mechanism of cytotoxicity induced by the co-treatment, further mechanistic and molecular studies are required to fully elucidate the enhanced anticancer effect of the co-treatment