Crossability of Arachis valida and B genome Arachis species.

The peanut (Arachis hypogaea) is an important food crop in much of the tropical and semi-tropical parts of the world. The peanut is an allotetraploid with an AABB genome formula derived from diploids A. duranensis (A genome) and A. ipaënsis (B genome). The success of an introgression program that aims to improve cultivated varieties of the peanut depends on whether the chosen B genome species is homologous with the B genome of the peanut. While not directly involved in the origin of the peanut to the best of our knowledge, Arachis valida is a B genome species that could potentially be a bridge species or a source of new and different alleles, because of its resistance to diseases and pests. In this study, we investigated the crossability of A. valida with five other B genome species of section Arachis. Eight cross-combinations were made with A. valida and A. gregoryi, A. ipaënsis, A. magna, A. valida, and A. williamsii. Two hundred and forty pollinations were made yielding 61 fruit segments, 61 seeds, one abortion, and 24 hybrid plants. An analysis of the morphological characteristics and pollen viability confirmed that the plants were hybrids. Our results indicated that higher pollen viability of hybrid plants corresponded with higher affinity between parent plants used in crossings. This conclusion corroborates much of previous research carried out by many other authors in the past.

Antibacterial activity of honey and propolis from Apis mellifera and Tetragonisca angustula against Staphylococcus aureus.

AIMS: The antibacterial activity against Staphylococcus aureus of honey and propolis produced by Apis mellifera and Tetragonisca angustula was evaluated. Secondary aims included the study of the chemical composition of propolis and honey samples and its relationship with antibacterial activity against S. aureus. METHODS AND RESULTS: The antibacterial activity of honey and propolis was determined by the method of macrodilution. The minimum inhibitory concentration (MICs) of A. mellifera honey ranged from 126.23 to 185.70 mg ml(-1) and of T. angustula from 142.87 to 214.33 mg ml(-1). For propolis, the MIC ranged from 0.36 to 3.65 mg ml(-1) (A. mellifera) and from 0.44 to 2.01 mg ml(-1) (T. angustula). Honey and propolis were evaluated by high-performance liquid chromatography. Some typical compounds of Brazilian propolis were also identified in honey samples. Principal component analysis revealed that the chemical composition of honey and propolis samples was distinct based on the geographical location of the samples. CONCLUSIONS: Propolis samples had higher antibacterial activity against S. aureus when compared with honey. However, both propolis and honey samples had antibacterial against S. aureus. SIGNIFICANCE AND IMPACT OF THE STUDY: These antimicrobial properties would warrant further studies on the clinical applications of propolis and honey against S. aureus.

Evaluation of phenolic compounds in Brazilian propolis from different geographic regions.

Chemometrics has been shown quite efficient to uncover relationships between chemical composition of a sample and its geographical origin. Forty propolis samples originated from the the South and South East of Brazil were analyzed by HPLC and 18 compounds of interest were studied which included: caffeic, p-coumaric and ferulic acids, and some of their derivatives, pinobanksin, a derivative of kaempferol and five phenolic compounds (assigned as 3-prenyl4-hydroxycinnamic acid (PHCA); 2,2-dimethyl-6-carboxyethnyl-2H-1-benzopyran (DCBE); 3,5-diprenyl-4-hydroxycinnamic acid (DHCA); compound E (still unknown) and 6-propenoic-2,2-dimethyl-8-prenyl-2H-1-benzopyran acid (DPB). Principal Component Analysis (PCA) indicated three different groups of propolis samples, having the same typical chromatogram, evaluated by HPLC. Samples from the South East group were rich in derivatives of kaempferol. Samples from the South group I had a high content of DPB compound, but a low concentration of kaempferol derivatives and of DCBEN compound. Samples from the South group II were characterized by a high concentration of DCBEN, DHCA, p-coumaric and DPB compounds. Therefore, the identification of new compounds in Brazilian propolis can give, useful information about the plant sources of a given geographic region.