Metabolomic Profiling of Antioxidant Compounds in Five Vachellia Species.

The genus Vachellia, previously known as Acacia, belongs to the family Fabaceae, subfamily Leguminosae, which are flowering plants, commonly known as thorn trees. They are traditionally used medicinally in various countries including South Africa for the treatment of ailments such as fever, sore throat, Tuberculosis, convulsions and as sedatives. The aim of this study was to determine biochemical variations in five Vachellia species and correlate their metabolite profiles to antioxidant activity using a chemometric approach. The antioxidant activity of five Vachellia aqueous-methanolic extracts were analyzed using three methods: 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) analysis and the ferric reducing antioxidant power (FRAP) assay by means of serial dilution and bioautography with the thin-layer chromatography (TLC) method. Amongst the Vachellia extracts tested, V. karroo, V. kosiensis and V. xanthophloea demonstrated the highest DPPH, ABTS+ and FRAP inhibitory activity. The antioxidant activities of DPPH were higher than those obtained by ABTS+, although these values varied among the Vachellia species. Proton nuclear magnetic resonance (1H NMR), coupled with multivariate statistical modeling tools such as principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), were performed to profile metabolites responsible for the observed activity. The OPLS-DA categorized the five Vachellia species, separating them into two groups, with V. karroo, V. kosiensis and V. xanthophloea demonstrating significantly higher radical scavenging activity than V. tortilis and V. sieberiana, which clustered together to form another group with lower radical scavenging activity. Annotation of metabolites was carried out using the ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-qTOF-MS), and it tentatively identified 23 metabolites of significance, including epigallocatechin (m/z = 305.0659), methyl gallate (m/z = 183.0294) and quercetin (m/z = 301.0358), amongst others. These results elucidated the metabolites that separated the Vachellia species from each other and demonstrated their possible free radical scavenging activities.

Comprehensive chemical characterization and biological evaluation of two Acacia species: A. nilotica and A. ataxacantha.

The genus Acacia (Family Leguminosae) is composed of several medicinal plants used for treating miscellaneous diseases. Amid the important members of this genus, A. nilotica and A. ataxacantha are widely employed for their tremendous healing properties. Hence, this present work aimed to determine the total phenolic and flavonoid contents and investigate the antioxidant, antiproliferative, anti-enzyme and antimicrobial potentials of methanolic and water extracts of leaves and stem bark of A. nilotica and A. ataxacantha obtained by maceration and ultrasonication. The total phenolic and flavonoid contents were obtained in the range of 33.35-116.60 mg GAE/g and 0.26-49.90 mg RE/g, respectively, with the methanolic leaf extracts of both species showing the highest contents. Moreover, the methanolic extracts were observed to display higher antioxidant potentials in almost all antioxidant assays performed compared to the water extracts (ABTS: 52.66-943.81 mg TE/g, DPPH: 8.51-493.90 mg TE/g, CUPRAC: 106.39-1193.75 mg TE/g; FRAP: 31.38-416.21 mg TE/g, and phosphomolybdenum: 0.90-4.17 mM TE/g). However, the water extracts were seen to be better metal chelators than the methanolic extracts (8.47-36.85 mg EDTAE/g). Additionally, all extracts were found to exhibit anti-tyrosinase (30.79-74.80 mg KAE/g) and anti-amylase (0.10-1.10 mM ACAE/g) properties. With the exception of a few extracts, glucosidase and acetylcholinesterase inhibitions (1.69-2.12 mg ACAE/g and 0.42-2.61 mg GALAE/g, respectively) were also demonstrated. While the methanolic extracts of both species showed antimicrobial potency against all the 18 tested microorganisms (gram positive, gram negative, and fungi), the water extracts were effective only against the gram positive bacteria. The extracts were also found to exhibit antiproliferative effects on SH-SY5Y human neuroblastoma cells, with the methanolic extracts showing higher cytotoxic potential than the water extracts. Therefore, this study showed these species to be good sources of antioxidants, enzyme inhibitors, antimicrobials and antiproliferative agents, which could be of great interest for their applications as natural bioactive ingredients in the development of pharmaceuticals and nutraceuticals.

The anti-inflammatory and antinociceptive effects of proteins extracted from Acacia farnesiana seeds / Efeito antiiflamatório e antinociceptivo de proteínas extraídas de sementes de Acacia farnesiana

ABSTRACT Seeds of Acacia farnesiana are commonly sold in the local markets of northeastern Brazil as a therapeutic agent. The present work aimed to evaluate the anti-inflammatory and analgesic activities of proteins obtained from A. farnesiana seeds. Five different protein fractions (albumin, globulin, prolamin, acidic and basic glutelins) were obtained and investigated for the protein pattern, the presence of hemagglutinating and proteolytic activities. The globulin fraction (GLB) was also evaluated for anti-inflammatory and analgesic activities. Globulins reduced the paw edema induced by carrageenan in a dose-dependent manner, which was accompanied by a reduction of myeloperoxidase activity (p < 0.05). Additionally, GLB reduced the neutrophil peritoneal migration induced by carrageenan. However, GLB was not able to inhibit the edema triggered by dextran. Pre-treatment with globulins reduced the abdominal constrictions induced by acetic acid as well as the paw licking time induced by formalin (69.1% at first phase). However, it did not produce a significant antinociceptive effect in the hot plate test (55-56 °C). Treating the GLB with heat (at 100 °C for 30 min) abolished its anti-edematogenic and hemagglutinating activities. Our results showed that seeds from A. farnesiana are a source of proteins with anti-inflammatory and analgesic properties.

RESUMO Sementes de Acacia farnesiana são comumente vendidas em feiras locais no nordeste do Brasil como agente terapêutico. O presente trabalho objetivou avaliar as atividades antiinflamatória e antinociceptiva de proteínas obtidas de sementes de A. farnesiana. Cinco frações protéicas distintas (albuminas, globulinas, prolaminas, glutelinas ácidas e básicas) foram obtidas e investigadas quanto o perfil de proteínas, presença de atividade hemaglutinante e proteolítica. A fração globulina (GLB) também foi avaliada quanto a presença de atividade antiinflamatória e analgésica. Globulinas reduziram o edema de pata induzido por carragenina de modo dependente da dose que foi acompanhada da redução da atividade da mieloperoxidase (p < 0,05). Em adição, GLB reduziu a migração de neutrófilos para cavidade peritoneal induzida por carragenina. Entretanto, GLB não foi capaz de inibir o edema induzido por dextrana. O pré-tratamento com globulinas reduziu as contorções abdominais induzidas por ácido acético, bem como o tempo de lambedura da pata induzida por formalina (69.1% na primeira fase). Por outro lado, GLB não produziu um efeito antinociceptivo significante no teste de placa quente (55-56 °C). O pré-tratamento de GLB com calor (100 °C por 30 min) aboliu sua atividade anti-edematogênica e hemaglutinante. Nossos resultados mostraram que sementes de A. farnesiana são fonte de proteínas com propriedades antiinflamatórias e analgésicas.

Leaf miner and plant galler species richness on Acacia: relative importance of plant traits and climate.

Diversity patterns of herbivores have been related to climate, host plant traits, host plant distribution and evolutionary relationships individually. However, few studies have assessed the relative contributions of a range of variables to explain these diversity patterns across large geographical and host plant species gradients. Here we assess the relative influence that climate and host plant traits have on endophagous species (leaf miners and plant gallers) diversity across a suite of host species from a genus that is widely distributed and morphologically variable. Forty-six species of Acacia were sampled to encapsulate the diversity of species across four taxonomic sections and a range of habitats along a 950 km climatic gradient: from subtropical forest habitats to semi-arid habitats. Plant traits, climatic variables, leaf miner and plant galler diversity were all quantified on each plant species. In total, 97 leaf mining species and 84 plant galling species were recorded from all host plants. Factors that best explained leaf miner richness across the climatic gradient (using AIC model selection) included specific leaf area (SLA), foliage thickness and mean annual rainfall. The factor that best explained plant galler richness across the climatic gradient was C:N ratio. In terms of the influence of plant and climatic traits on species composition, leaf miner assemblages were best explained by SLA, foliage thickness, mean minimum temperature and mean annual rainfall, whilst plant gall assemblages were explained by C:N ratio, %P, foliage thickness, mean minimum temperature and mean annual rainfall. This work is the first to assess diversity and structure across a broad environmental gradient and a wide range of potential key climatic and plant trait determinants simultaneously. Such methods provide key insights into endophage diversity and provide a solid basis for assessing their responses to a changing climate.

Ribotyping of rhizobia nodulating Acacia mangium and Paraserianthes falcataria from different geographical areas in Indonesia using PCR-RFLP-SSCP (PRS) and sequencing.

Acacia mangium and Paraserianthes falcataria are leguminous tree species widely grown for timber in Indonesia and other tropical countries, yet little is known about the identity of their rhizobial symbionts. Polymerase chain reaction-restriction fragment length polymorphism-single-strand conformational polymorphism (PRS) analysis of the 16S rRNA gene was used along with sequencing to assess the diversity of 57 rhizobia isolated from nodules of A. mangium and P. falctaria in Indonesia. In total, 26 rhizobia isolated from A. mangium were analysed by PRS and sequencing. The PRS patterns indicated that 12 (46%) clustered with Bradyrhizobium elkanii, 13 (50%) with B. lianoningense/japonicum and one (4%) with Mesorhizobium loti. Thirty-one isolates were analysed from P. falcataria: five (16%) clustered with B. elkanii and 26 (84%) with B. lianoningense/japonicum. These results were confirmed by phylogenetic analysis of sequences. Intraspecific diversity of the 16S rRNA genes from rhizobia nodulating A. mangium and P. falcataria revealed by PRS was low, only one genotype was found within the isolates that clustered with B. elkanii and two within the B. liaoningense/japonicum group. These Bradyrhizobium species are apparently ubiquitous throughout the Indonesian archipelago and it is clear why the two tree species are able to successfully establish outside their native range without the need for inoculation with indigenous rhizobia.