Larvicidal properties of simalikalactone d from Quassia africana (simaroubaceae) Baill and Baill, on the malaria vector Anopheles gambiae

Background: Botanical and microbial insecticides have been increasingly used for the control of mosquito given their efficacy and documented nontoxic effects on non-target organisms. The discovery of new insecticides is imperative because of the development of resistance by the mosquitoes to the readily available insecticides. The aim of this study was therefore to isolate and characterize compounds from a local medicinal plant, Quassiaafricana Baill and Baill (Simaroubaceae) that were toxic to Anopheles gambiae.Material and methods:The methanol extracts of the leaves, stem and roots of Quassia africana were tested against fourth instar larvae of An.gambiae. The root extract was partitioned into hexane, chloroform and ethyl acetate and the resulting extracts screened for larvicidal properties. The extracts and the fraction with the highest bioactivity were subjected to repeated column chromatography and isolated compounds evaluated forpotential toxicity to An. gambiae larvae. The structure of the active  compound was elucidated using spectroscopic techniques. The root extract showed the strongest activity profile (LC50 = 17.58 µg/mL). The chloroform soluble fraction obtained after partitioning the crude extract into solvents based on polarities was the most toxic. Further bio-activity-guided  chromatographic separation of the chloroform fraction of the root extract led to the identification and isolation of a simalikalactone D as the  larvicidal compound in Q. africana (LC50 = 1.25 µg/mL).Results: Results suggest that Q. africana may serve as a source for vector control agent for malaria.Conclusion: Simalikalactone D was identified as the larvicidal compound in Q. africana (LC50 = 1.25 µg/mL).Key words: vector control, larvicidal activity, spectroscop

Preliminary Phytochemical Analyses of Two Varieties of Adenia Lobata (Jacq) and the Antioxidant Activity of Their Various Solvent Fractions

Adenia lobata is a medicinal plant that is traditionally used for the treatment of various diseases such as cancer in some places in eastern Nigeria. Comparative phytochemical analyses were carried out on two varieties of Adenia lobata; Adenia lobata with cordate leaves (ALC) and Adenia lobata with palmate leaves (ALP). ALC was found to possess more phytochemical constituents than ALP. The antioxidant activity of the solvent fractions viz. hexane, dichloromethane (DCM), ethylacetate, butanol and aqueous fractions of each variety of the Adenia lobata was also determined. The highest antioxidant activity (63.87%) was found in the ethylacetate fraction of ALC. These results suggest that the therapeutic use of this plant in the treatment of cancer could be due to its antioxidant activity

GC-MS Analysis of Insecticidal Leaf Essential Oil of Pyrenacantha Staudtii Hutch and Dalz (Icacinaceae)

Purpose: Insecticides have been known to cause serious toxicological and environmental problems. Hence, the insecticidal activity and chemical composition of a local medicinal plant was investigated.Methods: Steam distillation of P.staudtii leaves was carried out using a Clavenger apparatus in order to obtain the volatile oils. Gas chromatography/mass spectrometric (GC/MS) analyses (DB-5 Optima-5 column) of the essential oil were performed and its insecticidalactivity determined.Results: GC-MS spectrometry showed that the major chemical components of the oil were tetradecanoic acid (22 %), hexanoic acid, α-phellandrene (13 %), and citronellol sp. (7 %). The work also revealed significant insecticidal activity of 80 % and 60 % against Rhyzoperthadominica and Tribolium castaneum, respectively.Conclusion: The study established the chemical composition and insecticidal activity of the essential oil of the plant leaf. Future formulation studies, toxicity profile and possible mechanism of action may lead to the development of a potential insecticidal product

Antiglycation Activity of Otostegia persica (Burm.) Boiss

Diabetes mellitus is a common endocrine disorder characterized by hyperglycemia and long-term complications affecting the eyes, nerves, blood vessels, skin and kidneys. Increased glycation of proteins and accumulation of advanced glycation endproducts (AGEPs) have been implicated in the pathogenesis of diabetic complications. Glycation and AGEP formation are also accompanied by the formation of free radicals via autoxidation of glucose and glycated proteins. Compounds with combined antiglycation and antioxidant properties may offer therapeutic potential. Since the antioxidant activity of different extracts and fractions of aerial parts of Otostegia persica has been evaluated and this plant is used as an antidiabetic agent in Iranian traditional medicine, we evaluated the antiglycation activity of this species. Here, we report the isolation of known compound 3´, 7-dihydroxy-4´,6,8-trimethoxy-flavone for the antiglycation properties of this plant

Parasiticidal, antifungal and antibacterial activities of Onosma griffithii Vatke

Onosma griffithii was screened for possible pharmacological activities. The crude methanolic extract (MeOH) and its fractions demonstrated parasiticidal activity (IC 50 (ìg/ml ± S.D) = 31.03 ± 0.23) against Leishmania major. Based on the IC 50 values, the potency of the standard drug (Pentamidine) and test fractions were of the order as: Pentamidine > crude extract > n-hexane fraction > ethyl acetate (ETOAc) fraction > chloroform fraction (CHCl3) fraction > n-butanol (BUOH) fraction > aqueous fraction. Similarlymoderate antifungal activity was displayed by the crude methanolic extract against Aspergillus flavus and Fusarium solani. Against the Staphylococcus aureus, the aqueous fraction demonstrated moderate antibacterial activity

Piptaderol From Piptadenia africana

A new glyceryl derivative (Glyceryl-1-hexacosanoate) and a flavone derivative (methyletherapigenin) were isolated from the stem bark extract of Piptadenia africana, a western Cameroonian plant species. Common terpenes like sitosterol, β-amyrin and eicosane were also isolated. These compounds were identified using physical and spectroscopic methods including mp, IR, 1H and 13C-NMR, DEPT, COSY, HMQC, HMBC, EI MS, HREI MS as well as some chemical transformations. The antibacterial activity of the extract, the fractions and the pure compounds is also discussed. Keywords: Piptadenia africana, Leguminoseae, Glyceryl-1-hexacosanoate, Methyletherapigenin, Chemotaxonomy, Antibacterial activity.African Journal of Traditional and Complementary Medicine Vol. 4 (3) 2007: pp. 294-29

Anti-glycation properties of Illicium verum Hook. f. fruit in-vitro and in a diabetic rat model

Background: Chronic hyperglycemic triggers the non-enzymatic glycation of biomolecules, resulting in the production of advanced glycation endproducts, that lead to several micro- and macrovascular complications. Therefore, the discovery of new, effective, and safe anti-glycation agents is an important need. One of the best choices for the management of diabetes is to use complementary and alternative medicinal therapies. Therefore, the present study was designed to evaluate the anti-glycation activity of ethanolic extract of Illicium verum Hook. f. (Star anise, a frequently used spice and medicinally important herb). Methods: The anti-glycation activity of ethanolic extract of Illicium verum Hook. f. was determined by using both in-vitro and in-vivo assays. HSA-fructose glycation model was employed to assess the in-vitro inhibition of protein glycation, additionally cross-linked AGEs (formed by incubating lysozyme with fructose) were assessed by SDS polyacrylamide gel electrophoresis. Dual inhibitory mechanisms, i.e., antioxidant and metal chelating activities, were also evaluated by using DPPH, ABTS, and Fe (II)-chelation assays. Acute toxicity of I. verum extract was also performed (by administrating different doses i.e. 2,000, 1,500, 1,000, and 500 mg/kg of body weight). Finally, in-vivo anti-glycation potential was evaluated by 7 weeks of administration of I. verum extract in streptozotocin-induced diabetic rats. Results: In HSA-fructose glycation model, extract of I. verum showed a good inhibitory activity with IC50 value of 0.11±0.001 mg/mL, as compared to the standard inhibitor, rutin (IC50 = 0.02±0.01 mg/mL). Extract of I. verum showed inhibitory activity in DPPH, and ABTS radical scavenging assays with IC50 values of 130±1.0, and 57±2.0 μg/mL, respectively, while it was found to be inactive in the Fe+2-chelation assay. The extract was found to be non-toxic, and reduce the elevated blood glucose, urea, lipid, liver function parameters, and renal AGEs levels in streptozotocin-induced diabetic rats. Conclusions: These results suggest that I. verum supplementation might help to reduce the burden of AGEs, and may have potential in preventing diabetes-associated complications

Bis-coumarins; non-cytotoxic selective urease inhibitors and antiglycation agents

© 2019 Elsevier Inc. The current study is concerned with the identification of lead molecules based on the bis-coumarin scaffold having selective urease inhibitory and antiglycation activities. For that purpose, bis-coumarins (1-44) were synthesized and structurally characterized by different spectroscopic techniques. Eight derivatives 4, 8-10, 14, 17, 34, and 40 demonstrated urease inhibition in the range of IC50 = 4.4 ± 0.21–115.6 ± 2.13 μM, as compared to standard thiourea (IC50 = 21.3 ± 1.3 μM). Especially, compound 17 (IC50 = 4.4 ± 0.21 μM) was found to be five-fold more potent than the standard. Kinetic studies were also performed on compound 17 in order to identify the mechanism of inhibition. Kinetic studies revealed that compound 17 is a competitive inhibitor. Antiglycation activity was evaluated using glycation of bovine serum albumin by methylglyoxal in vitro. Compounds 2, 11-13, 16, 17, 19–22, 35, 37, and 42 showed good to moderate antiglycation activities with IC50 values of 333.63–919.72 μM, as compared to the standard rutin (IC50 = 294.46 ± 1.5 μM). Results of both assays showed that the compounds with urease inhibitory activity did not show any antiglycation potential, and vice versa. Only compound 17 showed dual inhibition potential. All compounds were also evaluated for cytotoxicity. Compounds 17, 19, and 37 showed a weak toxicity towards 3 T3 mouse fibroblast cell line. All other compounds were found to be non-cytotoxic. Urease inhibition is an approach to treat infections caused by ureolytic bacteria whereas inhibition of glycation of proteins is a strategy to avoid late diabetic complications. Therefore, these compounds may serve as leads for further research

Stilbene glycosides are natural product inhibitors of FGF-2-induced angiogenesis

BACKGROUND: Angiogenesis, the growth of new blood vessels from the pre-existing vasculature is associated with pathological processes, in particular tumour development, and is a target for the development of new therapies. We have investigated the anti-angiogenic potential of two naturally occurring stilbene glycosides (compounds 1 and 2) isolated from the medicinal plant Boswellia papyriferai using large and smallvessel-derived endothelial cells. Compound 1 (trans-4',5'-dihydroxy-3-methoxystilbene-5-O-{alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->6)}-beta-D-glucopyranoside was the more hydrophilic and inhibited FGF-2-induced proliferation, wound healing, invasion in Matrigel, tube formation and angiogenesis in large and small vessel-derived endothelial cells and also in the chick chorioallantoic membrane assay. Using a binding assay we were able to show compound 1 reduced binding of FGF-2 to fibroblast growth factor receptors-1 and -2. In all cases the concentration of compound 1 which caused 50% inhibition (IC50) was determined. The effect of compound 1 on EGF and VEGF-induced proliferation was also investigated. RESULTS: Compound 1 inhibited all stages of FGF-2 induced angiogenesis with IC50 values in the range 5.8 +/- 0.18 - 48.90 +/- 0.40 microM but did not inhibit EGF or VEGF-induced angiogenesis. It also inhibited FGF-2 binding to FGF receptor-1 and -2 with IC50 values of 5.37 +/- 1.04 and 9.32 +/- 0.082 muM respectively and with concommotant down-regulation of phosphorylated-ERK-1/-2 expression. Compound 2 was an ineffective inhibitor of angiogenesis despite its structural homology to compound 1. CONCLUSION: Compound 1 inhibited FGF-2 induced angiogenesis by binding to its cognate receptors and is an addition to the small number of natural product inhibitors of angiogenesis