No abstract

Plants are reservoirs of bioactive compounds with the potential for pharmaceutical use. In this study, the secondary metabolites of Neonauclea formicaria leaf crude ethanolic extract were determined using phytochemical screening. The plant's leaf extract was then used to test its angiogenesis activity using the chorioallantoic membrane (CAM) assay. Four concentrations of the extract were prepared—0.1 mg/L, 1.0 mg/L, 10.0 mg/L, and 100.0 mg/L and were topically applied on the CAM. Phytochemical screening revealed that N. formicaria leaves contain heavy amounts of flavonoids and tannins, while alkaloids, saponins, and steroids were present in trace amounts. The crude ethanolic extract was anti-angiogenic, as indicated by the significant decrease of vascular density at higher concentrations (P<0.05).  The 100 mg/L extract concentration showed the highest vascular inhibition (50.93%) among the other concentrations, suggesting its angiopreventive potential (P<0.05). Further investigation on the embryo's gross morphometry revealed no significant effects in the weight, crown-rump length, head-beak length, forelimb length, and hind limb length. Also, these indices were not associated with the angiogenesis activity on the CAM. Further studies exploring the specific metabolites of the different plant parts of N. formicaria and the plant's angiopreventive potential are recommended.

No abstract

Understanding the stoichiometry of nitrogen (N) and phosphorus (P) plays a pivotal role in the ecological restoration of degraded landscapes. Here, the N and P limitation and stoichiometry of dominant tree species in mine-disturbed ultramafic areas in the Southern Philippines are reported. Field surveys revealed that out of a total of 1491 trees/shrubs recorded from all quadrats, comprising 22 native and 9 non-native species, there were six tree species (native: Alstonia macrophylla Wallich., Buchanania arborescens Blume., Syzygium sp., and non-native: Casuarina equisetifolia L., Terminalia catappa L. and Acacia mangium Wild.) that were found dominant, having >10% relative abundance. Significant differences (p < 0.01) in the leaf N and leaf P content among these species were observed, where C.equisetifolia (due to N fixation ability) and T. catappa had the highest values, respectively. These did not, however, translate to statistical differences in the leaf N:P ratios either in individual species or when grouped by origin (native or non-native). Interestingly, all dominant tree species revealed very low leaf N:P ratios (<4), suggesting that N rather than P limits the productivity in mine-disturbed ultramafic areas, which is also confirmed by low levels of leaf N (<2.0%). Results further revealed a poor correlation between leaf N and leaf N:P ratios (r = 0.13; p = 0.60), while leaf P (r = 0.49; p < 0.05) revealed otherwise, reinforcing that P is not a limiting factor as also shown in high levels of leaf P (>0.20%). Despite the N-limitation, B. arborescens, C. equisetifolia, and T. catappa had the highest leaf N and P content, suggesting their higher suitability for revegetation of the sites. These findings warrant further verification taking into account the plant physiology, phenology, and soil nutrient availability in natural, degraded, and rehabilitated ultramafic environments.