Costus afer Possesses Carbohydrate Hydrolyzing Enzymes Inhibitory Activity and Antioxidant Capacity In Vitro

Costus afer: A Systematic Review of Evidence-Based Data in support of Its Medicinal Relevance

Costus afer (C. afer) is a plant commonly known as ginger lily, spiral ginger, or bush cane. It is reportedly used in traditional medicine practice (TMP) to treat and manage many ailments including diabetes mellitus, stomach ache, arthritis, inflammation, and gout. These purported ethnomedicinal uses have triggered many research studies on the plant to amass scientific evidence. However, these research reports are scattered, and thus, this systematic review seeks to provide a comprehensive update on it covering its traditional uses, phytochemical and nutritional constituents, pharmacological activities, and toxicological effects. An online search was done using search engines such as Google Scholar, PubMed, and ScienceDirect from the period 1970 to 2019. The online search included the use of keywords, "Costus afer Ker-Gawl" or "Costus afer." The search revealed that the stem and leaves of the plant contain substantial amounts of micronutrients and macronutrients. The leaves, stem, rhizomes, and roots of C. afer contain several steroidal sapogenins, aferosides, dioscin, and paryphyllin C and flavonoid glycoside kaempferol-3-O-α-L-rhamnopyranoside. Experimental studies on various parts of the plant showed bioactivities such as antihyperglycemic, hepatocellular protection, cardioprotection, nephroprotection, testicular protection, CNS depressant, analgesic, antiarthritis, antibacterial, and antioxidant. Based on these evident data, it is concluded that the plant could be used as an alternative and complementary therapy for many oxidative stress-related diseases, provided further scientific studies on the toxicological and pharmacological aspects are carried out.

Phytomedicines Used for Diabetes Mellitus in Ghana: A Systematic Search and Review of Preclinical and Clinical Evidence

BACKGROUND

Available data indicate that diabetes mellitus leads to elevated cost of healthcare. This imposes a huge economic burden on households, societies, and nations. As a result many Ghanaians, especially rural folks, resort to the use of phytomedicine, which is relatively less expensive. This paper aims at obtaining information on plants used in Ghana to treat diabetes mellitus, gather and present evidence-based data available to support their uses and their mechanisms of action, and identify areas for future research.

METHOD

A catalogue of published textbooks, monographs, theses, and peer-reviewed articles of plants used in Ghanaian traditional medicine between 1987 and July 2018 for managing diabetes mellitus was obtained and used.

RESULTS

The review identified 76 plant species belonging to 45 families that are used to manage diabetes mellitus. Leaves were the part of the plants frequently used for most preparation (63.8%) and were mostly used as decoctions. Majority of the plants belonged to the Euphorbiaceae, Lamiaceae, Asteraceae, and Apocynaceae families. Pharmacological data were available on 23 species that have undergone in vitro studies. Forty species have been studied using in vivo animal models. Only twelve plants and their bioactive compounds were found with data on both preclinical and clinical studies. The records further indicate that medicinal plants showing antidiabetic effects did so via biochemical mechanisms such as restitution of pancreatic β-cell function, improvement in insulin sensitivity by receptors, stimulating rate of insulin secretion, inhibition of liver gluconeogenesis, enhanced glucose absorption, and inhibition of G-6-Pase, α-amylase, and α-glucosidase activities.

CONCLUSION

This review contains information on medicinal plants used to manage diabetes mellitus, including their pharmacological properties and mechanisms of action as well as models used to investigate them. It also provides gaps that can form the basis for further investigations and development into useful medications for effective treatment of diabetes mellitus.

Costus afer Protects Cardio-, Hepato-, and Reno-Antioxidant Status in Streptozotocin-Intoxicated Wistar Rats

Medicinal plants are efficient modulators of oxidative stress associated with diabetes mellitus. This study evaluated the cardio-, reno-, and hepato-antioxidant status of hydroethanolic extract of Costus afer on streptozotocin-intoxicated diabetic rats. Experimental animals were daily administered with hydroethanolic extract of C. afer by oral intubation for eight weeks (60 days), after which the levels of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and lipid peroxidation marker (MDA) were evaluated in the heart, liver, and kidney homogenates. Plasma biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total protein, creatinine, and urea were determined. Meanwhile, parts of the heart, kidneys, and liver were histopathologically examined. Streptozotocin administration induced toxicity in the cardiac, hepatic, and renal tissues by stimulating significant increases (p<0.05) in the levels of CAT and SOD, GSH, and MDA. Similarly, significant increases (P<0.05) in the levels of ALT, AST, urea, and total protein were observed in streptozotocin treated rats, whereas decreases were observed in the levels of ALP, LDH, and creatinine. Following the treatments with C. afer hydroethanolic extract prevented the effect of streptozotocin by maintaining the tissue antioxidant status (CAT, SOD, GSH, and MDA) and the plasma biochemical parameters (AST, ALT, ALP, LDH, creatinine, and urea) towards the normal ranges. The histopathological examination revealed hepatovascular congestion and leucocyte infiltration as well as renovascular congestion, glomerulosclerosis, and tubular clarification in the untreated diabetic control and their absence in the group of animals treated with a high dose of C. afer extract. The findings of the present investigation suggest that C. afer possesses antioxidant activities capable of regulating drug induced tissue damage.

Effect of Betula pendula Leaf Extract on α-Glucosidase and Glutathione Level in Glucose-Induced Oxidative Stress

B. pendula leaf is a common ingredient in traditional herbal combinations for treatment of diabetes in southeastern Europe. Present study investigated B. pendula ethanolic and aqueous extract as inhibitors of carbohydrate hydrolyzing enzymes, as well as their ability to restore glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress. Phytochemical analysis revealed presence of rutin and other quercetin derivatives, as well as chlorogenic acid. In general, ethanolic extract was richer in phenolic substances than the aqueous extract. Furthermore, a comprehensive analysis of antioxidant activity of two extracts (determined by DPPH and ABTS radical scavenging activity, total antioxidant activity, and chelating activity as well as ferric-reducing antioxidant power) has shown that ethanolic extract was better radical scavenger and metal ion reductant. In addition, ethanolic extract effectively increased cellular glutathione levels caused by hyperglycemia and inhibited α-glucosidase with the activity comparable to that of acarbose. Therefore, in vitro research using B. pendula plant extracts has confirmed their antidiabetic properties.