MyMedR

Displaying all 11 publications

Abstract:

Sort:

Ethnopharmacology of some Buddleja species

Houghton PJ

J Ethnopharmacol, 1984 Aug;11(3):293-308.
PMID: 6482480

Buddleja species play a minor role in the ethnopharmacology of several areas of the world where they are indigenous. Phytochemical investigation of the genus has been somewhat neglected but a picture is emerging of the type of constituents which are present in reasonable quantities, namely iridoid and flavonoid glycosides. Many of the uses of Buddleja in folk medicine such as a topical antiseptic and a diuretic can be partially explained at least by the known biological activity of compounds identical or similar to those found in the genus. Other reputed uses are, as yet, without explantation due to the incomplete state of knowledge of the chemistry and, to an even greater extent, the pharmacology of Buddleja.
Cytotoxicity of plants from Malaysia and Thailand used traditionally to treat cancer

Lee CC, Houghton P

J Ethnopharmacol, 2005 Sep 14;100(3):237-43.
PMID: 15888378

The SRB cytotoxicity assay was used to screen extracts and isolated constituents of some traditional medicinal plants from Malaysia and Thailand against two human cancer cell lines, COR L23 lung cancer cell line and MCF7 breast cancer cell line and the non-cancer MCF5 cell line. Five out of the seven species tested, i.e. Thai Alpinia galanga, Alpinia officinarum, Cayratia japonica, Physalis minima, Tabernaemontana divaricata, exhibited interesting cytotoxicity activity and this is the first report of cytotoxicity from any Cayratia species. Following bioassay-guided fractionation, 1'-acetoxychavicol acetate (48h exposure against COR L23 cells, IC(50) 7.8 microM against MCF7 cells, IC(50) 23.9 microM) was isolated as the major cytotoxic component of the Alpinia species, physalin F as the major cytotoxic component of Physalis minima (48 h exposure against COR L23 cells IC(50) 0.4 microM against MCF7 cells, IC(50) 0.59 microM). The Malaysian Alpinia galanga showed weak activity compared with the Thai sample and this was shown to be due to the relatively high amounts of 1'-acetoxychavicol acetate present in the Thai sample.
alpha-Amylase inhibitory activity of some Malaysian plants used to treat diabetes; with particular reference to Phyllanthus amarus

Ali H, Houghton PJ, Soumyanath A

J Ethnopharmacol, 2006 Oct 11;107(3):449-55.
PMID: 16678367

Extracts of six selected Malaysian plants with a reputation of usefulness in treating diabetes were examined for alpha-amylase inhibition using an in vitro model. Inhibitory activity studied by two different protocols (with and without pre-incubation) showed that Phyllanthus amarus hexane extract had alpha-amylase inhibitory properties. Hexane and dichloromethane extracts of Anacardium occidentale, Lagerstroemia speciosa, Averrhoa bilimbiPithecellobium jiringa and Parkia speciosa were not active when tested without pre-incubation. Extraction and fractionation of Phyllanthus amarus hexane extract led to the isolation of dotriacontanyl docosanoate, triacontanol and a mixture of oleanolic acid and ursolic acid. Dotriacontanyl docosanoate and the mixture of oleanolic acid and ursolic acid are reported from this plant species for the first time. All compounds were tested in the alpha-amylase inhibition assay and the results revealed that the oleanolic acid and ursolic acid (2:1) mixture was a potent alpha-amylase inhibitor with IC(50)=2.01 microg/ml (4.41 microM) and that it contributes significantly to the alpha-amylase inhibition activity of the extract. Three pure pentacyclic triterpenoids, oleanolic acid, ursolic acid and lupeol were shown to inhibit alpha-amylase.
Antimicrobial and antiinflammatory activities of extracts and constituents of Oroxylum indicum (L.) Vent

Mat Ali R, Houghton PJ, Raman A, Hoult JR

Phytomedicine, 1998 Oct;5(5):375-81.
PMID: 23195987 DOI: 10.1016/S0944-7113(98)80020-2

Dichloromethane extracts of the stembark and root of Oroxylum indicum were found to have antimicrobial activities against Gram positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gramnegative bacteria (Escherichia coli and Pseudomonas aeruginosa) and a yeast (Candida albicans). Bioassay-guided chromatographic fractionation led to the isolation of flavonoids (bacailein and chrysin) and a naphthoquinone, lapachol. Lapachol was found active against the Gram-positive bacteria, 5 μg giving a zone of inhibition equivalent to that shown by 5 μg streptomycin, whereas 5 μg chrysin gave inhibition zones of equal size to 5 μg streptomycin against Candida albicans and Pseudomonas aeruginosa. The inhibitory activity of lapachol from O. indicum root against soya 5-lipoxygenase (IC(50) 0.79 μg/ml) was equivalent to that of the positive control fisetin (IC(50) 0.97 μg/ml) and 50 μg/ml of the dichloromethane extract of the rootbark gave 100% inhibition of leukocyte lipoxygenase. These activities might indicate an antiinflammatory effect for the dichloromethane extract, mainly due to the lapachol content.
Ursolic acid from Mitragyna speciosa

Said IM, Chun NC, Houghton PJ

Planta Med, 1991 Aug;57(4):398.
PMID: 17226178
Fulltext Anticholinesterase inhibitory activity of quaternary alkaloids from Tinospora crispa

Yusoff M, Hamid H, Houghton P

Molecules, 2014 Jan 20;19(1):1201-11.
PMID: 24448061 DOI: 10.3390/molecules19011201

Quaternary alkaloids are the major alkaloids isolated from Tinospora species. A previous study pointed to the necessary presence of quaternary nitrogens for strong acetylcholinesterase (AChE) inhibitory activity in such alkaloids. Repeated column chromatography of the vine of Tinospora crispa extract led to the isolation of one new protoberberine alkaloid, 4,13-dihydroxy-2,8,9-trimethoxydibenzo[a,g]quinolizinium (1), along with six known alkaloids-dihydrodiscretamine (2), columbamine (3), magnoflorine (4), N-formylannonaine (5), N-formylnornuciferine (6), and N-trans-feruloyltyramine (7). The seven compounds were isolated and structurally elucidated by spectroscopic analysis. Two known alkaloids, namely, dihydrodiscretamine and columbamine are reported for the first time for this plant. The compounds were tested for AChE inhibitory activity using Ellman's method. In the AChE inhibition assay, only columbamine (3) showed strong activity with IC50 48.1 µM. The structure-activity relationships derived from these results suggest that the quaternary nitrogen in the skeleton has some effect, but that a high degree of methoxylation is more important for acetylcholinesterase inhibition.
Activity of extracts and naphthoquinones from Kigelia pinnata against Trypanosoma brucei brucei and Trypanosoma brucei rhodesiense

Moideen SV, Houghton PJ, Rock P, Croft SL, Aboagye-Nyame F

Planta Med, 1999 Aug;65(6):536-40.
PMID: 10483374

Dichloromethane extracts of the root bark and stem bark of Kigelia pinnata collected from Zimbabwe exhibited antitrypanosomal activity against Trypanosoma brucei brucei in vitro. Activity-guided fractionation led to the isolation of four naphthoquinones from both the root and stem bark of the plant. The compounds were identified as 2-(1-hydroxyethyl)-naphtho[2,3-b]furan-4,9-quinone (1), isopinnatal (2), kigelinol (3), and isokigelinol (4). Subsequently, the compounds were assessed for antitrypanosomal activity against T. brucei brucei and T. brucei rhodesiense bloodstream form trypomastigotes in vitro. Compound 1 with a furanonaphthoquinone structure was found to possess pronounced activity against both parasites with IC50 values of 0.12 and 0.045 microM, respectively, although it was less active than the standard drug pentamidine. Compounds 2, 3, and 4 also exhibited activity against the parasites, although to a lesser extent. The activities of the compounds were further assessed by comparison with the cytotoxic activities obtained against KB cell lines.
Genetic analysis of samples from wild populations opens new perspectives on hybridization between long-tailed (Macaca fascicularis) and rhesus macaques (Macaca mulatta)

Bunlungsup S, Kanthaswamy S, Oldt RF, Smith DG, Houghton P, Hamada Y, et al.

Am J Primatol, 2017 12;79(12).
PMID: 29095514 DOI: 10.1002/ajp.22726

In the past decade, many researchers have published papers about hybridization between long-tailed and rhesus macaques. These previous works have proposed unidirectional gene flow with the Isthmus of Kra as the zoogeographical barrier of hybridization. However, these reports analyzed specimens of unknown origin and/or did not include specimens from Thailand, the center of the proposed area of hybridization. Collected specimens of long-tailed and rhesus macaques representing all suspected hybridization areas were examined. Blood samples from four populations each of long-tailed and rhesus macaques inhabiting Thailand, Myanmar, and Laos were collected and analyzed with conspecific references from China (for rhesus macaques) and multiple countries from Sundaic regions (for long-tailed macaques). Ninety-six single nucleotide polymorphism (SNP) markers specifically designed to interrogate admixture and ancestry were used in genotyping. We found genetic admixture maximized at the hybrid zone (15-20°N), as well as admixture signals of varying strength in both directions outside of the hybrid zone. These findings show that the Isthmus of Kra is not a barrier to gene flow from rhesus to long-tailed populations. However, to precisely identify a southernmost barrier, if in fact a boundary rather than simple isolation by distance exists, the samples from peninsular Malaysia must be included in the analysis. Additionally, a long-tailed to rhesus gene flow boundary was found between northern Thailand and Myanmar. Our results suggest that selection of long-tailed and rhesus macaques, the two most commonly used non-human primates for biomedical research, should take into account not only the species identification but also the origin of and genetic admixture within and between the species.
Fulltext A genetic comparison of two alleged subspecies of Philippine cynomolgus macaques

Smith DG, Ng J, George D, Trask JS, Houghton P, Singh B, et al.

Am J Phys Anthropol, 2014 Sep;155(1):136-48.
PMID: 24979664 DOI: 10.1002/ajpa.22564

Two subspecies of cynomolgus macaques (Macaca fascicularis) are alleged to co-exist in the Philippines, M. f. philippensis in the north and M. f. fascicularis in the south. However, genetic differences between the cynomolgus macaques in the two regions have never been studied to document the propriety of their subspecies status. We genotyped samples of cynomolgus macaques from Batangas in southwestern Luzon and Zamboanga in southwestern Mindanao for 15 short tandem repeat (STR) loci and sequenced an 835 bp fragment of the mtDNA of these animals. The STR genotypes were compared with those of cynomolgus macaques from southern Sumatra, Singapore, Mauritius and Cambodia, and the mtDNA sequences of both Philippine populations were compared with those of cynomolgus macaques from southern Sumatra, Indonesia and Sarawak, Malaysia. We conducted STRUCTURE and PCA analyses based on the STRs and constructed a median joining network based on the mtDNA sequences. The Philippine population from Batangas exhibited much less genetic diversity and greater genetic divergence from all other populations, including the Philippine population from Zamboanga. Sequences from both Batangas and Zamboanga were most closely related to two different mtDNA haplotypes from Sarawak from which they are apparently derived. Those from Zamboanga were more recently derived than those from Batangas, consistent with their later arrival in the Philippines. However, clustering analyses do not support a sufficient genetic distinction of cynomolgus macaques from Batangas from other regional populations assigned to subspecies M. f. fascicularis to warrant the subspecies distinction M. f. philippensis.
Fulltext Distribution and prevalence of malaria parasites among long-tailed macaques (Macaca fascicularis) in regional populations across Southeast Asia

Zhang X, Kadir KA, Quintanilla-Zariñan LF, Villano J, Houghton P, Du H, et al.

Malar J, 2016 09 02;15(1):450.
PMID: 27590474 DOI: 10.1186/s12936-016-1494-0

BACKGROUND: Plasmodium knowlesi and Plasmodium cynomolgi are two malaria parasites naturally transmissible between humans and wild macaque through mosquito vectors, while Plasmodium inui can be experimentally transmitted from macaques to humans. One of their major natural hosts, the long-tailed macaque (Macaca fascicularis), is host to two other species of Plasmodium (Plasmodium fieldi and Plasmodium coatneyi) and is widely distributed in Southeast Asia. This study aims to determine the distribution of wild macaques infected with malarial parasites by examining samples derived from seven populations in five countries across Southeast Asia.
METHODS: Plasmodium knowlesi, P. cynomolgi, P. coatneyi, P. inui and P. fieldi, were detected using nested PCR assays in DNA samples from 276 wild-caught long-tailed macaques. These samples had been derived from macaques captured at seven locations, two each in the Philippines (n = 68) and Indonesia (n = 70), and one each in Cambodia (n = 54), Singapore (n = 40) and Laos (n = 44). The results were compared with previous studies of malaria parasites in long-tailed macaques from other locations in Southeast Asia. Fisher exact test and Chi square test were used to examine the geographic bias of the distribution of Plasmodium species in the macaque populations.
RESULTS: Out of 276 samples tested, 177 were Plasmodium-positive, with P. cynomolgi being the most common and widely distributed among all long-tailed macaque populations (53.3 %) and occurring in all populations examined, followed by P. coatneyi (20.4 %), P. inui (12.3 %), P. fieldi (3.4 %) and P. knowlesi (0.4 %). One P. knowlesi infection was detected in a macaque from Laos, representing the first documented case of P. knowlesi in wildlife in Laos. Chi square test showed three of the five parasites (P. knowlesi, P. coatneyi, P. cynomolgi) with significant bias in prevalence towards macaques from Malaysian Borneo, Cambodia, and Southern Sumatra, respectively.
CONCLUSIONS: The prevalence of malaria parasites, including those that are transmissible to humans, varied among all sampled regional populations of long-tailed macaques in Southeast Asia. The new discovery of P. knowlesi infection in Laos, and the high prevalence of P. cynomolgi infections in wild macaques in general, indicate the strong need of public advocacy in related countries.
Fulltext Ancestry, Plasmodium cynomolgi prevalence and rhesus macaque admixture in cynomolgus macaques (Macaca fascicularis) bred for export in Chinese breeding farms

Zhang X, Meng Y, Houghton P, Liu M, Kanthaswamy S, Oldt R, et al.

J Med Primatol, 2017 04;46(2):31-41.
PMID: 28266719 DOI: 10.1111/jmp.12256

BACKGROUND: Most cynomolgus macaques (Macaca fascicularis) used in the United States as animal models are imported from Chinese breeding farms without documented ancestry. Cynomolgus macaques with varying rhesus macaque ancestry proportions may exhibit differences, such as susceptibility to malaria, that affect their suitability as a research model.
METHODS: DNA of 400 cynomolgus macaques from 10 Chinese breeding farms was genotyped to characterize their regional origin and rhesus ancestry proportion. A nested PCR assay was used to detect Plasmodium cynomolgi infection in sampled individuals.
RESULTS: All populations exhibited high levels of genetic heterogeneity and low levels of inbreeding and genetic subdivision. Almost all individuals exhibited an Indochinese origin and a rhesus ancestry proportion of 5%-48%. The incidence of P. cynomolgi infection in cynomolgus macaques is strongly associated with proportion of rhesus ancestry.
CONCLUSIONS: The varying amount of rhesus ancestry in cynomolgus macaques underscores the importance of monitoring their genetic similarity in malaria research.