Chemical Profile and Antioxidant Capacity of Propolis from Tetragonula, Lepidotrigona, Lisotrigona and Homotrigona Stingless Bee Species in Vietnam.

The present study aimed to analyze and compare the chemical profile and antioxidant capacity of propolis from different bee species and different regions. The chemical profiles of propolis from six stingless bee species (Tetragonula iridipennis, T. laeviceps, Lepidotrigona terminata, L. ventralis, Lisotrigona carpenteri and Homotrigona apicalis) collected from a total of eight locations in Vietnam were investigated by gas chromatography-mass spectrometry (GC-MS). More than 70 compounds were identified, amongst which phenolic lipids (cardanols, resorcinols and anacardic acids), aromatic acids, triterpenes and xanthones. Taxonomic markers for Mangifera indica (phenolic lipids and cycloartane triterpenes) were detected in propolis from bees of the genera Tetragonula and Lepidotrigona, although in different amounts, whereas propolis from H. apicalis was characterized by triterpenes of the amyrine type, typical of dipterocarp trees. A clear discrimination between both groups was observed by principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). Propolis from Tetragonula and Lepidotrigona spp. and from Lisotrigona carpenteri, which is rich in xanthones, possesses higher radical scavenging and ferric-reducing capacity than that from H. apicalis. Propolis produced by all six stingless bee species in Vietnam was analyzed for the first time. In addition, this is the first report on L. carpenteri propolis.

Mangifera indica as propolis source: what exactly do bees collect?

OBJECTIVE: The mango tree Mangifera indica is known as one of the botanical sources of propolis in Tropical regions. There are two different materials which bees can collect from a mango tree to produce propolis: the resin of the tree bark, and the latex found on the fruits. We performed the study of the chemical profile of mango resin in comparison with propolis in order to clarify its importance as propolis source. RESULTS: We compared the chemical profiles (by GC-MS analysis of ethanol extracts after silylation) of the resin and samples of propolis: of stingless bees (3 Vietnames, 2 Indonesian), and one of Apis mellifera from Thailand. In the resin and all propolis samples, 25 compounds were identified: fatty acids, cardanols (alk(en)yl phenols), cardols, anacardic acids, triterpene alcohols and ketones, cycloartane type triterpenic acids. All samples have the same qualitative composition but there are important quantitative differences. Considering literature data on mango latex, we conclude that bees of different species, make use of the two propolis sources offered by mango: bark resin and fruit latex, in different proportions. We also confirmed for the first time the presence of alk(en)yl phenols and anacardic acids in the tree bark resin of mango.

New dihydrochromene and xanthone derivatives from Lisotrigona furva propolis.

A new dihydrochromene derivative, named lisofurvin (1) and a xanthone, named dihydrobrasixanthone B (2) together with twenty one known compounds (3-23) were isolated from propolis of the stingless bee Lisotrigona furva. Their chemical structures were determined by means of spectroscopic methods including 1D and 2D NMR, and MS. The chemical constituents are predominantly geranyl(oxy) xanthones and Cratoxylum cochinchinense was suggested as a resin source, besides two other plants Mangifera indica and dammar trees (Dipterocarpaceae). Compound 1 showed significant cytotoxic activity against KB, HepG-2, and Lu-1 cancer cell lines with IC50 values range from 12.63 to 15.17 µg/mL. Several isolated compounds were active against one to four tested cancer cell lines. In addition, among the isolated compounds, α-mangostin (15) displayed the strongest antimicrobial activity against three Gram (+) strains, P. aeruginosa, and C. albicans with MIC values ranging between 1 and 2 µg/mL. Compound 22 showed good activity against three Gram (+) strains and C. albicans.

Contribution to the taxonomy of the paper wasp genus Polistes (Polistella) (Hymenoptera: Vespidae: Polistinae) from Vietnam, with description of a new species.

One species of the genus Polistes, Polistes (Polistella) caobangensis Nguyen, sp. nov. is described from the northern part of Vietnam. In addition, males of two other species, Polistes (Polistella) gilvus Nguyen, Kojima and Saito and Polistes (Polistella) brunus Nguyen and Carpenter are also described for the first time.

Discovery of four new species of Trichrysis Lichtenstein, cyanea species group (Hymenoptera, Chrysididae) from Vietnam.

Four species of the genus Trichrysis Lichtenstein, 1876 are described from Vietnam as new for science: T. aliciae Wisniowski, sp. nov., T. chamchuensis Wisniowski Nguyen, sp. nov., T. kylan Wisniowski Cuong, sp. nov., and T. raymundi Wisniowski, sp. nov. The species belong to the T. cyanea species group.

Taxonomic notes on the genus Pseumenes Giordani Soika, 1935 (Hymenoptera: Vespidae: Eumeninae) from Vietnam with key to all known species in the Oriental region.

There are two species of the genus Pseumenes Giordani Soika, 1935 occurring in Vietnam, Pseumenes depressus depressus (de Saussure, 1855) and a new species, Pseumenes fulvus Nguyen. The new species is described and figured. A key to all known species of this genus from the Oriental region is provided.

Phytochemical analysis of Vietnamese propolis produced by the stingless bee Lisotrigona cacciae.

Propolis produced by the stingless bee Lisotrigona cacciae was studied for the first time. Using different chromatographic procedures, a total of eighteen constituents (phenols and triterpenes) were isolated, among which flavane 1, homoisoflavanes 2-4, and xanthones 5 and 6 were new for propolis. Propolis extract was also characterized by gas chromatography/mass spectrometry and other fifteen constituents were identified. The xanthone α-mangostin (8) demonstrated significant activity against Staphylococcus aureus with MIC and MBC 0.31 µg/ml, followed by 7,4'-dihydroxy-5-methoxy-8-methylflavane (1) with MIC 78 µg/ml and MBC 156 µg/ml. 10,11- Dihydroxydracaenone C (4), a component bearing ortho-hydroxyl groups, was the only compound displaying radical scavenging ability. Triple botanical origin of the sample was defined, consisting of Dracaena cochinchinensis, Cratoxylum cochinchinense and Mangifera indica. D. cochinchinensis is a new resin source of propolis.

Acceptability and Feasibility of Delivering Pentavalent Vaccines in a Compact, Prefilled, Autodisable Device in Vietnam and Senegal.

BACKGROUND: Prefilled syringes are the standard in developed countries but logistic and financial barriers prevent their widespread use in developing countries. The current study evaluated use of a compact, prefilled, autodisable device (CPAD) to deliver pentavalent vaccine by field actors in Senegal and Vietnam. METHODS: We conducted a logistic, programmatic, and anthropological study that included a) interviews of immunization staff at different health system levels and parents attending immunization sessions; b) observation of immunization sessions including CPAD use on oranges; and c) document review. RESULTS: Respondents perceived that the CPAD would improve safety by being non-reusable and preventing needle and vaccine exposure during preparation. Preparation was considered simple and may reduce immunization time for staff and caretakers. CPAD impact on cold storage requirements depended on the current pentavalent vaccine being used; in both countries, CPAD would reduce the weight and volume of materials and safety boxes thereby potentially improving outreach strategies and waste disposal. CPAD also would reduce stock outages by bundling vaccine and syringes and reduce wastage by using a non-breakable plastic presentation. Respondents also cited potential challenges including ability to distinguish between CPAD and other pharmaceuticals delivered via a similar mechanism (such as contraceptives), safety, and concerns related to design and ease of administration (such as activation, ease of delivery, and needle diameter and length). CONCLUSIONS: Compared to current pentavalent vaccine presentations in Vietnam and Senegal, CPAD technology will address some of the main barriers to vaccination, such as supply chain issues and safety concerns among health workers and families. Most of the challenges we identified can be addressed with health worker training, minor design modifications, and health messaging targeting parents and communities. Potentially the largest remaining barrier is the marginal increase in pentavalent cost--if any--from CPAD use, which we did not assess in our study.

Human papillomavirus vaccine introduction in Vietnam: formative research findings.

BACKGROUND: Formative research is a useful tool for designing new health interventions. This paper presents key findings from formative research conducted in Vietnam to guide human papillomavirus (HPV) vaccine introduction. METHODS: We explored the sociocultural environment, health system capacity and the policy-making process using a combined quantitative and qualitative methodology. Data collection was done through literature review, in-depth interviews, focus group discussions, observation checklists and a structured questionnaire on knowledge, attitudes and practices. Populations of interest included 11- to 14-year-old girls, their parents, community leaders, teachers, health workers, health and education officials, and policy-makers at all levels. RESULTS: Although HPV vaccines are new, we found high potential acceptance among parents and girls. HPV vaccine introduction was also favourably supported by health professionals if assurances for system preparedness, e.g. cold chain and human resources, were made. There were no significant barriers from the policy perspective that would prevent the introduction of a new vaccine. However, several concerns related to this new vaccine would need to be adequately addressed before implementation. CONCLUSION: Our findings provide options for potential vaccine delivery strategies, appropriate communication strategies and targeted advocacy strategies to introduce HPV vaccines in the Vietnamese context.

Community knowledge, attitudes, and practices toward rabies prevention in North Vietnam.

In recent years, despite the accessibility to vaccines (both for humans and animals), rabies remains a problem in many areas of Vietnam. While the number of rabies deaths decreased by 90% from 1994 to 2003, the number of rabies deaths increased from 2004 to 2007. In 2007, the number of rabies victims was 2-3 times higher than in 2003 and 131 people died as a result of rabies. In order to better understand Knowledge, Attitudes, and Practices (KAP) toward rabies in areas of both high and low incidence of rabies mortality in Vietnam, and KAP between pet and non-pet owners, a cross-sectional study was carried out by administering a structured questionnaire to 585 respondents from selected households in Thanh Son District-Phu Tho Province and Viet Yen District-Bac Giang Province, Vietnam. KAP in both high and low incidence areas, especially in groups with pets, need to be improved, particularly regarding treatment practices after a dog-bite and recommended pet care. We recommend not only enhanced IEC activities, but also the development of a Behavior Change Communication Strategy (BCC).