Investigation of the Phytochemistry and Antioxidant Activity of Pterocarpus angolensis (Mubvamaropa) from Mupandawana

The present study investigated the phytochemistry and antioxidant activity of Pterocarpus angolensis (Mubvamaropa) from Mupandawana. Pt. angolensis has numerous medicinal uses. The bark, sap, leaves and roots are all used to treat different ailments. The sap is used to stop nose bleeds, treatment of ulcers and kill ringworms. Several studies have supported the use of the tree’s sap to treat cataracts, malaria as well as skin inflammations. Pterocarpus angolensis bark was collected from Gutu, Masvingo province and authenticated by a plant taxonomist at the Zimbabwe National herbarium (Mr Chapano). The bark was cleaned using distilled water and oven dried at 40°C for 4 hours to constant weight. Size reduction was achieved using a Thomas-Wiley laboratory mill model with a 2 mm sieve mesh. The phytochemical analysis revealed that the ethanolic extract had more phyto-constituents than the water extract which only four phyto-constituents present all of which were weakly positive. DPPH scavenging activity was 95.11% at a concentration of 500 μg/mL bark extract, while that of the control, ascorbic acid, was 97.60%. Ascorbic acid had an IC50 value of 4.35 µg/mL while the bark extract had a value of 150.64 µg/mL.

CROWN MORPHOMETRY FOR TWO VALUABLE TIMBER SPECIES FROM MIOMBO WOODLAND IN MOZAMBIQUE

Pterocarpus angolensis DC and Bobgunnia madagascariensis (Desv.) J. H. Kirkbr. & Wiersema are two hardwood species found in Miombo woodland. Crown size, being closely related to the photosynthetic capacity of a tree, is an important parameter in studies of the growth of individual trees. In this sense, the present study aimed to study the morphometric relationships of P. angolensis and B. madagascariensis as a resource to describe the morphometric features of these species. Data were sampled in 60 rectangular plots of 20 x 50 m, systematically distributed within the forest. In each plot, the diameter at breast height (DBH), height (h), crown insertion point (cih) and four crown radii of all trees with DBH ≥ 10 cm were measured. Results indicated that crown diameter and crown length of P. angolensis grow as DBH and height increase, the larger the crown, the greater the trees dimensions; as for B. madagascariensis, crown features have shown low correlation when considering DBH. It was concluded that crown features influence on tree growth and are important measures of description and planning of silvicultural activities to be performed in natural forests. The results are of interest to forest managers since they make decisions about silvicultural operations. Keywords: crown dimensions; prediction models; umbila; pau-ferro; forest management.

Root Nodule Rhizobia From Undomesticated Shrubs of the Dry Woodlands of Southern Africa Can Nodulate Angolan Teak Pterocarpus angolensis, an Important Source of Timber

Pterocarpus angolensis, a leguminous tree native to the dry woodlands of Southern Africa, provides valuable timber, but is threatened by land conversion and overharvesting while showing limited natural regeneration. Nitrogen-fixing root nodule symbionts that could improve establishment of young seedlings have not yet been described. Therefore, we investigated the ability of P. angolensis to form nodules with a diverse range of rhizobia. In drought-prone areas under climate change with higher temperatures, inoculants that are heat-tolerant and adapted to these conditions are likely to be of advantage. Sources of bacterial isolates were roots of P. angolensis from nurseries in the Kavango region, other shrubs from this area growing near Pterocarpus such as Indigofera rautanenii, Desmodium barbatum, Chamaecrista sp., or shrubs from drought-prone areas in Namaqualand (Wiborgia monoptera, Leobordea digitata) or Kalahari (Indigofera alternans). Only slight protrusions were observed on P. angolensis roots, from which a non-nodulating Microbacterium sp. was isolated. Rhizobia that were isolated from nodules of other shrubs were affiliated to Bradyrhizobium ripae WR4T, Bradyrhizobium spp. (WR23/WR74/WR93/WR96), or Ensifer/Mesorhizobium (WR41/WR52). As many plant growth-promoting rhizobacteria (PGPR), nodule isolates produced siderophores and solubilized phosphate. Among them, only the Bradyrhizobium strains nodulated P. angolensis under controlled conditions in the laboratory. Isolates were further characterized by multilocus sequence analysis and were found to be distant from known Bradyrhizobium species. Among additional reference species tested for nodulation on P. angolensis, Bradyrhizobium vignae 7-2T and Bradyrhizobium namibiense 5-10T from the Kavango region of Namibia as well as Bradyrhizobium elkanii LMG6234T and Bradyrhizobium yuanmingense LMG21728T induced nitrogen-fixing nodules, while Bradyrhizobium diazoefficiens USDA110T and Bradyrhizobium tropiciagri SEMIA6148T did not. This suggests a broad microsymbiont range from Bradyrhizobium japonicum and B. elkanii lineages. Phylogenetic analysis of nodC genes indicated that nodulating bradyrhizobia did not belong to a specific symbiovar. Also, for I. rautanenii and Wiborgia, nodule isolates B. ripae WR4T or Mesorhizobium sp. WR52, respectively, were authenticated. Characterization of symbionts inducing effective root nodules in P. angolensis and other shrubs from Subsahara Africa (SSA) give insights in their symbiotic partners for the first time and might help in future to develop bioinoculants for young seedlings in nurseries, and for reforestation efforts in Southern Africa.

Population structure, harvesting rate and regeneration status of four woody species in Kimboza forest reserve, Morogoro region - Tanzania

Kimboza forest reserve is recognized as an IUCN category IV-habitat and species management area, but the information on population structure, harvesting rate and regeneration status of four commercial woody species, namely; Khaya anthotheca, Milicia excelsa, Pterocarpus angolensis and Dalbergia melanoxylon in the forest are lacking. This study, therefore, aims to fill this gap. A total of five transects were established in the forest whereby within each transect, five nested quadrats of 20 m × 20 m were placed at 200 m distance for sampling stems with diameter at breast height (DBH) ≥ 10 cm and stumps of the target species. Stems with DBH <10 cm were counted in a quadrat of 5 m × 5 m placed within the big quadrat. The findings show that density of stems & harvesting rate for Khaya anthotheca, Milicia excelsa, Pterocarpus angolensis and Dalbergia melanoxylon were 4.8 stems ha-1 & 6.6 stumps ha-1, 12.6 stems ha-1 & 3.4 stumps ha-1, 16.0 stems ha-1 & 2.8 stumps ha-1, and 5.6 stems ha-1 & 1.2 stumps ha-1, respectively. The DBH class distribution for Khaya anthotheca, Milicia excelsa and Pterocarpus angolensis displayed a good regeneration pattern, however, the last two were interrupted in high size classes. The Dalbergia melanoxylon revealed a poor regeneration pattern. The study recommends that illegal harvest of the species should be controlled, environmental education be provided to locals, and stringent measures be institutionalized against illegal loggers.

Julbernardia paniculata and Pterocarpus angolensis: From Ethnobotanical Surveys to Phytochemical Characterization and Bioactivities Evaluation

Julbernardia paniculata and Pterocarpus angolensis are two plant species with important application in African traditional medicine, particularly in Angola, in the treatment of several diseases. However, scientific studies concerning these species are scarce. The goal of this work was to know better which medicinal approaches are used by the Huíla population in Angola by means of ethnobotanical surveys. Furthermore, extracts of both plants were phytochemically characterized. Antioxidant, anti-inflammatory, wound-healing activities, and potential cytotoxicity were also studied. With this study it was possible to verify that 67% of the individuals that use medicinal plants are women, and their main therapeutic uses are the treatment of problems of the digestive system and skin disorders. Barks of J. paniculata and leaves of P. angolensis are the most often used plant parts. Through high-performance liquid chromatography coupled to diode-array detector (HPLC-DAD) and GC-MS it was possible to characterize the chemical composition of the two species, which are rich in phenolic compounds, terpenes, terpenoids, sesquiterpenoids and fatty acids. Both plants showed to possess antioxidant, anti-inflammatory proprieties, and wound-healing activity. To the best of our knowledge, this is the most comprehensive study of these two species and the first ethnobotanical and ethnopharmacological study of medicinal plants from this region of Angola.

The anatomy as a tool for the identification of the bark of Pterocarpus angolensis and Terminalia sericea

Pterocarpus angolensis and Terminalia sericea are two African species with medicinal potential. Despite the importance of their bark as a powerful astringent to treat various diseases it is poor described. In order to provide referential information for correct identification and standardization of the plant material, bark samples from each two species were collected and analyzed under light and electron microscopy. Some important anatomical features to identification were: the sclerenchyma tissue mostly in form of fibre-sclereids and the large secretory cells arranged in conspicuous rows or tangential bands in the conducting phloem in P. angolensis; the crystalliferous cells arranged in very regular tangential rows (druses) and the occurrence of large crystal cells near or including the tangential fibre bundles in T. sericea bark.The results obtained show that the anatomy of the bark can be used as an important subsidy in identification and standardization of the studied species contributing the scientific knowledge for more effective forms of scrutiny in preventing commercial adulteration of species.