Schistosomiasis is the second most prevalent tropical disease in the world after malaria. Chemoth... more Schistosomiasis is the second most prevalent tropical disease in the world after malaria. Chemotherapy and molluscicides which are the main methods of control do not give lasting protection as the disease continues to spread to other new regions. Previous studies have demonstrated the immunogenic properties of the digestive gland (DG), foot parts (FT) and the rest of body tissue (RT) soluble protein of Biomphalaria pfeifferi against Schistosoma parasite and therefore possible candidates for vaccine development against the parasite. However, information about the chemical composition of the soluble proteins is scanty. The objective of this study was to characterize and determine chemical composition of the DG and FT soluble proteins from Biomphalaria pfeifferi. A total of twelve compounds were identified using GC-MS. N-tert-butyl methylamine and penicillamine were present in both DG and FT soluble proteins. Butylamine S, valine, amino heptanoic acid, 1,1-dimethylamino-1 butane and va...
7a-Acetylugandensolide together with thirteen known drimane-type sesquiterpenes have been isolate... more 7a-Acetylugandensolide together with thirteen known drimane-type sesquiterpenes have been isolated from Warbugia ugandensis bark extracts. Their structures were established by spectroscopic and physical methods as well as comparison with data available in the literature. The in vitro antimicrobial activities of the extracts and isolates were investigated against fungi and bacteria which infect sweet potato. Ethyl acetate extract exhibited the highest (P � 0.05) antifungal and antibacterial activities compared to nhexane and methanol extracts. Rhizopus stolonifer was more susceptible to ethyl acetate extract (inhibition zone = 24.5 mm) than Blitox which was used as a positive control. The minimum inhibitory concentration (MIC) for the isolates ranged between 12.5 and 200 mg/ml with the lowest MIC value of 12.5 mg/ml being observed with polygodial against Fusarium solani; warburganal against Aspergillus niger and F. solani; and mukaadial against A. niger
Chemical analysis of the acetone extract of Commiphora holtziana gum resin has led to the isolati... more Chemical analysis of the acetone extract of Commiphora holtziana gum resin has led to the isolation of triterpenes characterized as methyl 3-oxo-1α,19α,28-trihydroxyurs-12-en-24-oate (1), methyl 3β-acetyl-2α,11α,19α,28-tetrahydroxyurs-12-en-24-oate (2), methyl 3β,11α-diacetyl-1α,2α,28-trihydroxyurs-12-ene-24-oate (3), and 3β,28-diacetyl-1α,2α,25-trihydroxydammar-23-ene (4). The known compounds isolated from the same extract included cabraleadiol monoacetate (5), mansumbinol (6), 3β-acetylamyrin (7), 3α-acetylboswellic acid (8), 2-methoxy-8,12-epoxygermacra-1(10),7,11-trien-6-one (9), 2-methoxy-5-acetylfuranogermacra-1(10),7,11-trien-6-one (10), furadienone (11), 2-methoxy-5-acetyl-4-furanogermacra-1(10)Z-en-6-one (12), α-amyrin (13), sistosterol (14) and stigmasterol 3-O-acetate (15). Structural elucidation was carried out using spectroscopic and physical methods as well as by comparison with the literature data.
Sitophilus zeamais and Prostephanus truncatus, the destructive pests of maize in Africa, cause ex... more Sitophilus zeamais and Prostephanus truncatus, the destructive pests of maize in Africa, cause extensive tunneling in maize grain leading to conversion of maize grain into flour within a very short time. Small-scale farmers are often forced to sell maize shortly after harvest to minimize losses during storage, thereby attract low prices and compromising food security. Most available pesticides have adverse effects on environment and humans. The aim of this study was to evaluate efficacy of extracts and compounds of Warburgia ugandensis in controlling of S. zeamais and P. truncatus. Chromatographic fractionation of extracts from W. ugandensis afforded 7α-acetylugandensolide (1), ugandensolide (2), polygodial (3), warbuganal (4), ugandensidial (5), mukaadial (6) and muzigadial (7). The structures of the compounds were determined using spectroscopic and physical methods. n-Hexane extract was the most repellent among the extracts while polygodial (3) was the most repellent compound agai...
National Commission for Science, Technology and Innovation (NACOSTI) Kenya Medical Research Insti... more National Commission for Science, Technology and Innovation (NACOSTI) Kenya Medical Research Institute (KEMRI) Mr. Simon Mathenge
Insect pests cause significant loss of maize production in Africa. Among pests of maize, beetles ... more Insect pests cause significant loss of maize production in Africa. Among pests of maize, beetles are the most important, with the maize weevil (Sitophilus zeamais Motsch.) and the larger grain borer (Prostephanus truncatus Horn.) being the major pests. The extensive tunneling in maize grain by S. zeamais and P. trancatus adults allows them to convert grain into flour within a very short time. Synthetic pesticides are available in the market. However, such pesticides have adverse effects on non-targeted organisms and also persist in the environment and accumulate in the food chain. Plant have been reported to contain secondary metabolites some of which are toxic to pests as well as pathogenic microorganism The use of botanical in pests and disease control is preferred because they are safe and non-toxic to humans. This study investigated the efficacy of Ocimum suave Willd in management of maize weevil. The essential oil, hexane, ethyl acetate and methanol extracts as well as powdered...
Insect pests cause significant loses to maize grains in storage. Larger grain borer (Prostephanus... more Insect pests cause significant loses to maize grains in storage. Larger grain borer (Prostephanus truncatus Horn) is one of the most important pests of stored maize. Synthetic pesticides are commercially available for managing the pests. However, some of the chemicals have been banned from use because of their adverse effects on environment and living organisms. Therefore, it is necessary the search for alternative control methods that are effective and environmentally friendly. This study determined the repellence activity of extracts and compounds from Ocimum suave for control of P. truncatus. Repellence activity was measured after exposing the insects to test materials for 2, 5, 24, 48 and 96 hours. Chromatographic analysis of extracts from O. suave yielded five compounds and were identified as β-sitosterol, stigmasterol, β-amyrin, lupeol and betulinic acid. The insects were repelled most by the essential oil (mean repellency = 4.61 cm) with repellence distances of 5.83 and 5.38 ...
Three flavonoids, quercetin 3-O-β-D-glucoside (1), quercetin 3-O-α-D-arabinoside (2) and kaempfer... more Three flavonoids, quercetin 3-O-β-D-glucoside (1), quercetin 3-O-α-D-arabinoside (2) and kaempferol 3-O-β-D-galactoside (3) were isolated from the methanol leaf extract of Annona mucosa. Their structures were determined using physical and spectroscopic methods. compound 1 showed the highest activity against both S. zeamais and P. truncatus with LC50 values of 20.891 μg/ml and 22.241μg/ml, respectively though lower than the activity of deltamethrine a commercial insecticide used as a positive control. Compounds 2 and 3 gave moderate toxicities with LC50 values of 21.745 μg/ml and 24.926 μg/ml for compound 2 and 29.260μg/ml and 24.241μg/ml for compound 3 when tested against S. zeamais and P. truncates, respectively. compounds 1, 2 and 3 were also tested for anti-feedant activities against S. zeamais and P. truncatus and they exhibited interesting results. The activities were concentration dependent, increasing with increase in concentration. Quercetin 3-O-β-D-glucoside (1) showed the ...
Herbal medicine has been used for many years and it remains widespread in developing countries wh... more Herbal medicine has been used for many years and it remains widespread in developing countries while the use of complementary alternative medicine is increasing rapidly in developed countries. Senna didymobotrya is important for its medicinal use among many communities to treat a wide range of ailments. The study examines the patterns of morphological variation and phenetic relationships among 39 populations of S. didymobotrya in Kenya using17 quantitative and 17 qualitative characters. A survey was carried out in Siaya, Kisumu, Nandi and Nakuru Counties to collect S . didymobotrya plants. Results on morphometric analysis indicated that the standard deviations were highly significant when all quantitative characters were considered. Stem diameter, plant height and stem height had the highest standard deviation of 13.14, 11.74 and 11.15 respectively. Leaf length and Internodal length had the lowest standard deviations of 0.18 each. Principal component analysis indicated that the plan...
Drimane sesquiterpenes are important group of phytochemicals with a wide range of medicinal prope... more Drimane sesquiterpenes are important group of phytochemicals with a wide range of medicinal properties including antibacterial, antifungal, anti-inflammatory, antioxidant, antiplasmodial, antileishmanial, molluscicidal, antifeedant and insecticidal features. Due to their wide range of medicinal activities, scientists are prompted to continuously search for novel drimane sesquiterpenes since most of the currently available anti-infective agents have drawbacks such as drug resistance and side effects. Structure determination of new compounds relies on accurate interpretation of spectroscopic data which is quite challenging but can be simplified by comparison with the data of known related compounds from the reliable databases. A large number of drimane sesquiterpenes have been examined by 13C NMR spectroscopy but such data are scattered in the literature making it hard for researchers to use them. This paper provides a review on previously reported drimane sesquiterpenes and a compila...
Chemical investigation of CH 2 Cl 2 and MeOH extracts of Conyza floribunda have led to the isolat... more Chemical investigation of CH 2 Cl 2 and MeOH extracts of Conyza floribunda have led to the isolation of (24S)-ethylcholesta-5, 22E, 25-trien-3- O -glucosyl (1”→ 4’)-rhamnoside ( 1 ), (24S)-ethylcholesta-5,25-dien-3- O -α-glucoside ( 2 ), cyasterone ( 3 ), stigmasta 5, 22-dien-3-acetate ( 4 ), stigmasta 5, 22-dien-3-ol ( 5 ), spinasta 7, 22-dien-3-ol ( 6 ), 3-oxofriedooleanane ( 7 ), 3-hydroxyfriedooleanane ( 8 ), 3-acetoxyfriedooleanane ( 9 ), betullinic acid ( 10 ), quercetin 3- O -α-glucoside ( 11 ), quercetin ( 12 ), myricetin ( 13 ) and kaempferol ( 14 ). Their structures were determined using spectroscopic and physical methods as well as comparison with data available in the literature. Keywords: Conyza floribunda , asteraceae, triterpenes, sterols, flavonols
Schistosomiasis is the second most prevalent tropical disease in the world after malaria. Chemoth... more Schistosomiasis is the second most prevalent tropical disease in the world after malaria. Chemotherapy and molluscicides which are the main methods of control do not give lasting protection as the disease continues to spread to other new regions. Previous studies have demonstrated the immunogenic properties of the digestive gland (DG), foot parts (FT) and the rest of body tissue (RT) soluble protein of Biomphalaria pfeifferi against Schistosoma parasite and therefore possible candidates for vaccine development against the parasite. However, information about the chemical composition of the soluble proteins is scanty. The objective of this study was to characterize and determine chemical composition of the DG and FT soluble proteins from Biomphalaria pfeifferi. A total of twelve compounds were identified using GC-MS. N-tert-butyl methylamine and penicillamine were present in both DG and FT soluble proteins. Butylamine S, valine, amino heptanoic acid, 1,1-dimethylamino-1 butane and va...
7a-Acetylugandensolide together with thirteen known drimane-type sesquiterpenes have been isolate... more 7a-Acetylugandensolide together with thirteen known drimane-type sesquiterpenes have been isolated from Warbugia ugandensis bark extracts. Their structures were established by spectroscopic and physical methods as well as comparison with data available in the literature. The in vitro antimicrobial activities of the extracts and isolates were investigated against fungi and bacteria which infect sweet potato. Ethyl acetate extract exhibited the highest (P � 0.05) antifungal and antibacterial activities compared to nhexane and methanol extracts. Rhizopus stolonifer was more susceptible to ethyl acetate extract (inhibition zone = 24.5 mm) than Blitox which was used as a positive control. The minimum inhibitory concentration (MIC) for the isolates ranged between 12.5 and 200 mg/ml with the lowest MIC value of 12.5 mg/ml being observed with polygodial against Fusarium solani; warburganal against Aspergillus niger and F. solani; and mukaadial against A. niger
Chemical analysis of the acetone extract of Commiphora holtziana gum resin has led to the isolati... more Chemical analysis of the acetone extract of Commiphora holtziana gum resin has led to the isolation of triterpenes characterized as methyl 3-oxo-1α,19α,28-trihydroxyurs-12-en-24-oate (1), methyl 3β-acetyl-2α,11α,19α,28-tetrahydroxyurs-12-en-24-oate (2), methyl 3β,11α-diacetyl-1α,2α,28-trihydroxyurs-12-ene-24-oate (3), and 3β,28-diacetyl-1α,2α,25-trihydroxydammar-23-ene (4). The known compounds isolated from the same extract included cabraleadiol monoacetate (5), mansumbinol (6), 3β-acetylamyrin (7), 3α-acetylboswellic acid (8), 2-methoxy-8,12-epoxygermacra-1(10),7,11-trien-6-one (9), 2-methoxy-5-acetylfuranogermacra-1(10),7,11-trien-6-one (10), furadienone (11), 2-methoxy-5-acetyl-4-furanogermacra-1(10)Z-en-6-one (12), α-amyrin (13), sistosterol (14) and stigmasterol 3-O-acetate (15). Structural elucidation was carried out using spectroscopic and physical methods as well as by comparison with the literature data.
Sitophilus zeamais and Prostephanus truncatus, the destructive pests of maize in Africa, cause ex... more Sitophilus zeamais and Prostephanus truncatus, the destructive pests of maize in Africa, cause extensive tunneling in maize grain leading to conversion of maize grain into flour within a very short time. Small-scale farmers are often forced to sell maize shortly after harvest to minimize losses during storage, thereby attract low prices and compromising food security. Most available pesticides have adverse effects on environment and humans. The aim of this study was to evaluate efficacy of extracts and compounds of Warburgia ugandensis in controlling of S. zeamais and P. truncatus. Chromatographic fractionation of extracts from W. ugandensis afforded 7α-acetylugandensolide (1), ugandensolide (2), polygodial (3), warbuganal (4), ugandensidial (5), mukaadial (6) and muzigadial (7). The structures of the compounds were determined using spectroscopic and physical methods. n-Hexane extract was the most repellent among the extracts while polygodial (3) was the most repellent compound agai...
National Commission for Science, Technology and Innovation (NACOSTI) Kenya Medical Research Insti... more National Commission for Science, Technology and Innovation (NACOSTI) Kenya Medical Research Institute (KEMRI) Mr. Simon Mathenge
Insect pests cause significant loss of maize production in Africa. Among pests of maize, beetles ... more Insect pests cause significant loss of maize production in Africa. Among pests of maize, beetles are the most important, with the maize weevil (Sitophilus zeamais Motsch.) and the larger grain borer (Prostephanus truncatus Horn.) being the major pests. The extensive tunneling in maize grain by S. zeamais and P. trancatus adults allows them to convert grain into flour within a very short time. Synthetic pesticides are available in the market. However, such pesticides have adverse effects on non-targeted organisms and also persist in the environment and accumulate in the food chain. Plant have been reported to contain secondary metabolites some of which are toxic to pests as well as pathogenic microorganism The use of botanical in pests and disease control is preferred because they are safe and non-toxic to humans. This study investigated the efficacy of Ocimum suave Willd in management of maize weevil. The essential oil, hexane, ethyl acetate and methanol extracts as well as powdered...
Insect pests cause significant loses to maize grains in storage. Larger grain borer (Prostephanus... more Insect pests cause significant loses to maize grains in storage. Larger grain borer (Prostephanus truncatus Horn) is one of the most important pests of stored maize. Synthetic pesticides are commercially available for managing the pests. However, some of the chemicals have been banned from use because of their adverse effects on environment and living organisms. Therefore, it is necessary the search for alternative control methods that are effective and environmentally friendly. This study determined the repellence activity of extracts and compounds from Ocimum suave for control of P. truncatus. Repellence activity was measured after exposing the insects to test materials for 2, 5, 24, 48 and 96 hours. Chromatographic analysis of extracts from O. suave yielded five compounds and were identified as β-sitosterol, stigmasterol, β-amyrin, lupeol and betulinic acid. The insects were repelled most by the essential oil (mean repellency = 4.61 cm) with repellence distances of 5.83 and 5.38 ...
Three flavonoids, quercetin 3-O-β-D-glucoside (1), quercetin 3-O-α-D-arabinoside (2) and kaempfer... more Three flavonoids, quercetin 3-O-β-D-glucoside (1), quercetin 3-O-α-D-arabinoside (2) and kaempferol 3-O-β-D-galactoside (3) were isolated from the methanol leaf extract of Annona mucosa. Their structures were determined using physical and spectroscopic methods. compound 1 showed the highest activity against both S. zeamais and P. truncatus with LC50 values of 20.891 μg/ml and 22.241μg/ml, respectively though lower than the activity of deltamethrine a commercial insecticide used as a positive control. Compounds 2 and 3 gave moderate toxicities with LC50 values of 21.745 μg/ml and 24.926 μg/ml for compound 2 and 29.260μg/ml and 24.241μg/ml for compound 3 when tested against S. zeamais and P. truncates, respectively. compounds 1, 2 and 3 were also tested for anti-feedant activities against S. zeamais and P. truncatus and they exhibited interesting results. The activities were concentration dependent, increasing with increase in concentration. Quercetin 3-O-β-D-glucoside (1) showed the ...
Herbal medicine has been used for many years and it remains widespread in developing countries wh... more Herbal medicine has been used for many years and it remains widespread in developing countries while the use of complementary alternative medicine is increasing rapidly in developed countries. Senna didymobotrya is important for its medicinal use among many communities to treat a wide range of ailments. The study examines the patterns of morphological variation and phenetic relationships among 39 populations of S. didymobotrya in Kenya using17 quantitative and 17 qualitative characters. A survey was carried out in Siaya, Kisumu, Nandi and Nakuru Counties to collect S . didymobotrya plants. Results on morphometric analysis indicated that the standard deviations were highly significant when all quantitative characters were considered. Stem diameter, plant height and stem height had the highest standard deviation of 13.14, 11.74 and 11.15 respectively. Leaf length and Internodal length had the lowest standard deviations of 0.18 each. Principal component analysis indicated that the plan...
Drimane sesquiterpenes are important group of phytochemicals with a wide range of medicinal prope... more Drimane sesquiterpenes are important group of phytochemicals with a wide range of medicinal properties including antibacterial, antifungal, anti-inflammatory, antioxidant, antiplasmodial, antileishmanial, molluscicidal, antifeedant and insecticidal features. Due to their wide range of medicinal activities, scientists are prompted to continuously search for novel drimane sesquiterpenes since most of the currently available anti-infective agents have drawbacks such as drug resistance and side effects. Structure determination of new compounds relies on accurate interpretation of spectroscopic data which is quite challenging but can be simplified by comparison with the data of known related compounds from the reliable databases. A large number of drimane sesquiterpenes have been examined by 13C NMR spectroscopy but such data are scattered in the literature making it hard for researchers to use them. This paper provides a review on previously reported drimane sesquiterpenes and a compila...
Chemical investigation of CH 2 Cl 2 and MeOH extracts of Conyza floribunda have led to the isolat... more Chemical investigation of CH 2 Cl 2 and MeOH extracts of Conyza floribunda have led to the isolation of (24S)-ethylcholesta-5, 22E, 25-trien-3- O -glucosyl (1”→ 4’)-rhamnoside ( 1 ), (24S)-ethylcholesta-5,25-dien-3- O -α-glucoside ( 2 ), cyasterone ( 3 ), stigmasta 5, 22-dien-3-acetate ( 4 ), stigmasta 5, 22-dien-3-ol ( 5 ), spinasta 7, 22-dien-3-ol ( 6 ), 3-oxofriedooleanane ( 7 ), 3-hydroxyfriedooleanane ( 8 ), 3-acetoxyfriedooleanane ( 9 ), betullinic acid ( 10 ), quercetin 3- O -α-glucoside ( 11 ), quercetin ( 12 ), myricetin ( 13 ) and kaempferol ( 14 ). Their structures were determined using spectroscopic and physical methods as well as comparison with data available in the literature. Keywords: Conyza floribunda , asteraceae, triterpenes, sterols, flavonols
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