Chemosystematic and evolutionary trends of the genistoid clade sensu stricto (Papilionoideae, Fabaceae)

The Papilionoideae, which comprises 503 genera and approximately 14,000 species, is the largest and most diverse subfamily of the Fabaceae family. In this subfamily, the Crotalarieae, Genisteae, Podalyrieae, Thermopsideae, Sophoreae and Euchresteae tribes are closely related by micro and macromolecular features, thus forming the genistoid clade. This group combines well-known genera, whereas other genera lack phytochemical and chemotaxonomic studies. Thus, this work aimed to characterize the special metabolites in these genera in order to define the chemical profile, the micromolecular markers and the chemical diversity, as well as to evaluate the group evolutionary trends. Flavonoids and alkaloids were identified as chemosystematic markers for the studied tribes due to high occurrence number and structural diversity. Among flavonoids, the flavones and isoflavones predominated. Low protection indexes of flavonoid hydroxyls by O-glycosylation or O-methylation were observed, whereas C-prenylation and C-glycosylation were frequent, mainly at C-6 and C-8 positions. The flavone/flavonol ratio shows the predominance of the flavones. Quinolizidine and piperidine alkaloids were present in most genera. Pyrrolizidine alkaloids were found in a few genera from Thermopsideae, Genisteae and Crotalarieae, which suggests a mechanism of adaptive convergence. Cluster analysis allowed separation of genera for each tribe by chemical similarities. The micromolecular trends of protection of flavonoid hydroxyls and alkaloid oxidation indicate the genistoid clade is through evolutionary transition, which is consistent with its phylogenetic position in the Papilionoideae subfamily.

Fatty Acid Profile and Squalene, Tocopherol, Carotenoid, Sterol Content of Seven Selected Consumed Legumes

Legume seeds (Fabaceae) of seven species Cyamopsis tetragonoloba (guar), Glycine max (soybean), Lablab purpureus (lablab-bean), Macrotyloma uniflorum (kulthi bean), Phaseolus vulgaris (common bean), Trigonella foenum-graecum (fenugreek) and Vigna unguiculata (cowpea) were studied. The oil yield ranged from 1.2 to 20.2% dw, in the lablab-bean and soybean, respectively. The polyunsaturated fatty acids (PUFA) constituted the largest part (46-78%) of total fatty acids in studied legumes. γ-Tocopherol was the predominant tocopherol (T) homologue (61-95%) in most of the tested legumes with the exception of fenugreek (α-T, 97%) and cowpea (γ-T and δ-T, nearly equal). The β-sitosterol was the main sterol (51-56%) in most legumes. While in cowpea, lablab-bean and kulthi bean the main sterols were β-sitosterol and Δ5-stigmasterol (28-37% and 14-42%, respectively). Squalene was detected only in kulthi bean and lablab-bean (58 and 284 mg/100 g oil). The total concentration of carotenoids, tocochromanols, and sterols in the studied legumes was 0.2-9.2, 12.4-276.0, and 350-8,542 mg/100 g oil, respectively. Based on the levels of minor lipophilic compounds of this study, C. tetragonoloba, T. foenum-graecum and G. max seem to have a better nutritional value compared to P. vulgaris, V. unguiculata, L. purpureus, and M. uniflorum.

Insights into the diversification of subclade IVa bHLH transcription factors in Fabaceae

BACKGROUND

Fabaceae plants appear to contain larger numbers of subclade IVa basic-helix-loop-helix (bHLH) transcription factors than other plant families, and some members of this subclade have been identified as saponin biosynthesis regulators. We aimed to systematically elucidate the diversification of this subclade and obtain insights into the evolutionary history of saponin biosynthesis regulation in Fabaceae.

RESULTS

In this study, we collected sequences of subclade IVa bHLH proteins from 40 species, including fabids and other plants, and found greater numbers of subclade IVa bHLHs in Fabaceae. We confirmed conservation of the bHLH domain, C-terminal ACT-like domain, and exon-intron organisation among almost all subclade IVa members in model legumes, supporting the results of our classification. Phylogenetic tree-based classification of subclade IVa revealed the presence of three different groups. Interestingly, most Fabaceae subclade IVa bHLHs fell into group 1, which contained all legume saponin biosynthesis regulators identified to date. These observations support the co-occurrence and Fabaceae-specific diversification of saponin biosynthesis regulators. Comparing the expression of orthologous genes in Glycine max, Medicago truncatula, and Lotus japonicus, orthologues of MtTSAR1 (the first identified soyasaponin biosynthesis regulatory transcription factor) were not expressed in the same tissues, suggesting that group 1 members have gained different expression patterns and contributions to saponin biosynthesis during their duplication and divergence. On the other hand, groups 2 and 3 possessed fewer members, and their phylogenetic relationships and expression patterns were highly conserved, indicating that their activities may be conserved across Fabaceae.

CONCLUSIONS

This study suggests subdivision and diversification of subclade IVa bHLHs in Fabaceae plants. The results will be useful for candidate selection of unidentified saponin biosynthesis regulators. Furthermore, the functions of groups 2 and 3 members are interesting targets for clarifying the evolution of subclade IVa bHLH transcription factors in Fabaceae.

The complete chloroplast genome sequence of Sainfoin (Onobrychis viciifolia)

Sainfoin (Onobrychis viciifolia) is one of the dominant legume forages distributed in Northern China. In our study, we assembled and annotated the structure of the complete chloroplast genome of sainfoin. The length of the circular genome is 122,102 bp. It contains 115 genes, including 79 protein-coding genes (68.7%), 31 tRNA genes (26.96%) and 5 rRNA genes (4.35%). The GC content of the total chloroplast genome of sainfoin is 34.58%. We construct the phylogenetic relationships between the chloroplast genome of sainfoin and the other 16 species by the Maximum likelihood (ML), and found sainfoin is most closely related to Hedysarum petrovii and Hedysarum taipeicum.

The complete chloroplast genome of a pantropical legume, Canavalia rosea

We assembled a complete chloroplast genome of a pantropical legume, Canavalia rosea (Fabaceae). The chloroplast genome was 158,059 bp in length that was composed of a 77,752 bp large single copy region, a 18,993 bp small single copy region, and a pair of 30,657 bp inverted repeats. We detected 135 genes that consisted of 90 protein-coding genes, 37 tRNA genes, eight rRNA genes, and three pseudogenes (rps16 and a pair of rpl22).

Bioengineering of an elastase inhibitor from Caesalpinia echinata (Brazil wood) seeds

Protease inhibitors have been widely used in several therapeutic applications such as in the treatment of bleeding disorders, hypertension, cancer and pulmonary diseases. In a previous work, we demonstrated that a Kunitz-type serine protease inhibitor isolated from the seeds of Caesalpinia echinata (CeEI) exhibits pharmacological potential in lung inflammatory diseases in which neutrophil elastase plays a crucial role. However, an important challenge in the use of natural products is to ensure a commercially viable production. In this work, we report the cloning, expression and purification of two recombinant CeEI isoinhibitors with 700 base pairs encoding two proteins with 181 amino acid residues (rCeEI-4 and rCeEI-5). After the expression, each yielding 22 mg/L of active protein, both isoinhibitors presented a molecular mass of about 23.0 kDa, evaluated by SDS-PAGE. The inhibition constants for human neutrophil elastase (HNE) were 0.67 nM (rCeEI-4) and 0.57 nM (rCeEI-5), i.e., similar to the native inhibitor (1.90 nM). Furthermore, rCeEI-4 was used as a template to design smaller functional peptides flanking the inhibitor reactive site: rCeEI-36, delimited between the amino acid residues N³⁶ and S⁸⁸ containing a disulfide bond in the reactive-site loop, and rCeEI-46, delimited between S⁴⁶ and L⁷⁵ without the disulfide bond. The yields were 18 mg/L (rCeEI-36) and 12 mg/L (rCeEI-46). Both peptides inhibit HNE in the nanomolar range (K_i 0.30 ± 0.01 and 8.80 ± 0.23, respectively). Considering their size and the inhibitory efficiency, these peptides may be considered in strategies for the development of drugs targeting pulmonary disorders where elastase is involved.

Complete Genome Sequencing Provides Novel Insight Into the Virulence Repertories and Phylogenetic Position of Dry Beans Pathogen Curtobacterium flaccumfaciens pv. flaccumfaciens

Bacterial wilt of dry beans (family Fabaceae) caused by the actinobacterial agent Curtobacterium flaccumfaciens pv. flaccumfaciens is one of the most important diseases threatening edible legume production around the globe. Despite the economic losses due to the bacterial wilt disease, the pathogen has not so far been investigated for its genomic features, pathogenicity determinants, and virulence strategies. Here we present the first complete genome sequence of a highly virulent bacteriocin-producing C. flaccumfaciens pv. flaccumfaciens strain P990. The bacterium has a circular chromosome consisting of 3,736 kbp with the G+C% content of 71.0%. Furthermore, a 147-kbp circular plasmid (pCff1) with 66.1% G+C% content as well as two circular plasmid-like DNAs with sizes of 25 and 22 kbp were detected within the genomic contents of C. flaccumfaciens pv. flaccumfaciens. Phylogenetic analyses revealed that only a few number of Curtobacterium sp. strains deposited in the public databases could be classified within the species C. flaccumfaciens. Comparative genomics of C. flaccumfaciens pv. flaccumfaciens using the genome sequences of actinobacterial plant pathogens revealed the presence of a set of unique low G+C% content genomic islands in the C. flaccumfaciens pv. flaccumfaciens genome. Homologs of pathogenicity-determinant loci capable of producing 1,4-beta-xylanase (xysA), pectate lyase (pelA1 and pelA2), serine protease (chpC, chpG, and pat-1), and sortase (srtA) were detected in C. flaccumfaciens pv. flaccumfaciens genome. The genomic data presented here extend our understanding of the C. flaccumfaciens pv. flaccumfaciens genomic features and pave the ways of research on functional and interaction genetics to combat the risk of bacterial wilt disease in the 21st century's dry bean industry.

Plastome of Saraca asoca (Detarioideae, Fabaceae): Annotation, comparison among subfamily and molecular typing

Saraca asoca (Roxb.) Willd. (subfamily Detarioideae, family Fabaceae) is a perennial evergreen sacred medicinal tree classified under 'vulnerable' by the IUCN. The chloroplast (cp) genome/plastome which follows uniparental inheritance contains many useful genetic information because of its conservative rate of evolution. The assembled cp genome of S. asoca which maps as a conserved circular structure revealed extensive rearrangement in gene organization, comprising total length 160,003 bp including LSC, SSC, IRa, and IRb, and GC content was 35.26%. Herein a set of rbcL and matK gene were established using molecular phylogenetic analyses for molecular typing of S. asoca.

A taxonomic study of twelve wild forage species of Fabaceae

Twelve species of wild leguminosae were studied to determine similarities in the coat details of the seeds using a Scanning Electron Microscope (SEM). The numerical cluster analysis method was used to examine the morphological characteristics (98 characteristics) and to clarify the taxonomic relationship between the studied species (6 genera and 3 tribes) belonging to the Fabaceae family. The relevant wild species were: Lotus edulis L, Lotus ornithopodioides L., Tetragonolobus purpureus Moench, Medicago laciniata (L.) Mill., Gard. Dict., M.orbicularis (L.) Bart., M.turbinata (L.) All, M.polymorpha L., Ononis vaginalis Vahl, Lathyrus aphaca L., Vicia sativa L., V. peregrine L., and V.tetrasperma (L.) Schreb. The aim of this study was to produce a taxonomy reflecting the relations between these twelve forage species of Fabaceae by using the morphological and SEM features to provide a details about and clarify the relations between the examined taxa. The taxonomic histories of the Fabaceae family were reviewed. The results of the morphological description and SEM showed that it was possible to distinguish between the taxa using the cluster analysis attributes for the differences in characteristic correlation between the groups under study. This study will help researchers better grasp the classification of these species of legumes which were chosen because of the difficulty of differentiating between them, their environment benefits, their use for human consumption and pasture. The SEM is a suitable tool for this analysis, owing to the similarities exhibited by the seeds.

Plastid phylogenomic insights into the evolution of subfamily Dialioideae (Leguminosae)

The subfamily Dialioideae (Leguminosae) consists of 17 genera and about 85 species. Previous studies have detected significant plastid genome (plastome) structure variations in legumes, particularly in subfamilies Papilionoideae and Caesalpinioideae. Hence it is important to investigate plastomes from the newly recognized Dialioideae to better understand the plastome variation across the whole family. Here, we used nine plastomes representing nine genera of Dialioideae to explore plastome structural variation and intergeneric relationships in this subfamily. All plastomes of Dialioideae exhibited a typical quadripartite structure, and had relatively conserved structure compared with other legume subfamilies. However, the genome size ranged from 154,124 bp to 165,973 bp and gene numbers ranged from 129 to 132, mainly due to the expansion and contraction of the inverted repeat (IR) regions. The IR of Distemonanthus benthamianus has experienced two separate expansions into the large single copy (LSC) region and the small single copy (SSC) region, and one contraction from SSC. Poeppigia procera has experienced two separate IR expansions into LSC, while Dicorynia paraensis has experienced an IR contraction from LSC. Highly divergent regions or genes (ndhC-trnV ^UAC ,psbK-trnQ ^UUG,rps19-rps3,rpl33-rps18,accD-psaI,trnG ^UCC -trnS ^GCU ,psbI-trnS ^GCU ,5'rps16-trnQ ^UUG and ycf1) were identified as potential molecular markers for further species delimitation and population genetics analysis in legumes. Phylogenetic analysis based on 77 protein-coding sequences fully resolved the intergeneric relationships among nine genera except a moderately supported sister relationship between Petalostylis labicheoides and Labichea lanceolata. Our study reveals new insights into the structural variations of plastomes in subfamily Dialioideae and advances our understanding of the evolutionary trajectories of legume plastomes.

Iridopsis socoromaensis sp. n., a geometrid moth (Lepidoptera, Geometridae) from the Andes of northern Chile

Background

Iridopsis Warren, 1894 (Lepidoptera: Geometridae: Ennominae: Boarmiini) is a New World moth genus mainly diversified in the Neotropical Region. It is represented in Chile by two described species, both from the Atacama Desert.

New information

Iridopsis socoromaensis sp. n. (Lepidoptera: Geometridae: Ennominae: Boarmiini) is described and illustrated from the western slopes of the Andes of northern Chile. Its larvae were found feeding on leaves of the Chilean endemic shrub Dalea pennellii (J.F. Macbr.) J.F. Macbr. var. chilensis Barneby (Fabaceae). Morphological differences of I. socoromaensis sp. n. with the two species of the genus previously known from Chile are discussed. A DNA barcode fragment of I. socoromaensis sp. n. showed 93.7-94.3% similarity with the Nearctic I. sanctissima (Barnes & McDunnough, 1917). However, the morphology of the genitalia suggests that these two species are distantly related. The discovery of I. socoromaensis sp. n. highlights the need for additional surveys in underexplored areas to understand better the taxonomic diversity and evolutionary relationships of the mainly Neotropical moth genus Iridopsis.

Plant-Soil-Microbiota Combination for the Removal of Total Petroleum Hydrocarbons (TPH): An In-Field Experiment

The contamination of soil with total petroleum hydrocarbons (TPH) may result in dramatic consequences and needs great attention, as soil rehabilitation would need more effort from a sustainability perspective. However, there is still no known general method since the remediation technology is strictly site-specific. Adaptive biological system dynamics can play a key role in understanding and addressing the potential of situ-specific biological combinations for soil pollutants removal. The potential worst-case of TPH contamination reflects soil affected by heavy industrial activities, such as oil refineries. Therefore, the experimental trial was conducted on a 2,000 m2 area from a contaminated site located in northern Italy. We evaluated the remediation potential over time (270 days) assessing (i) the phytoremediation efficiency of two species of Poaceae (Festuca arundinacea Schreb. and Dactylis glomerata L.) and two species of Fabaceae (Medicago sativa L. and Lotus corniculatus L.) and (ii) the role of the indigenous bacteria flora and endo-mycorrhizae consortium addition in plant growth promotion. We also induced resistance to contamination stress in a field experiment. Thirty-three indigenous bacteria selected from the contaminated soils showed marked plant growth promotion. Moreover, functional metagenomics confirmed the metabolic capability of hydrocarbon-degrading microorganisms living in the polluted soil. Our data showed that soil enzymatic activities increased with hydrocarbon degradation rate after 60 days. Both Poaceae and Fabaceae resulted in remarkable remediation potential. Stress markers and antioxidant activity indicated that the selected plant species generally need some time to adapt to TPH stress. In conclusion, our evaluation implied both the rhizosphere effects and functional features of the plant and suggested that plants should (i) have marked tolerance to specific contaminants, (ii) be characterized by an extensive root system, and (iii) be susceptible to arbuscular mycorrhizal fungi (AMF) infection.

Characteristics of complete chloroplast genome of a high-quality forage on Qinghai-Tibet Plateau, Medicago archiducis-nicolai Sirj. (Fabaceae：Trifolieae)

Medicago archiducis-nicolai Sirj. is a well-known high-quality forage as its good palatability and strong tolerance to drought, cold and saline-alkali stress. Here, the complete chloroplast genome sequence of M. archiducis-nicolai was reported. The size of the complete chloroplast genome is 127,072 bp in length. The chloroplast genome has no inverted repeat (IR) regions, which is very common in the family Fabaceae. The M. archiducis-nicolai chloroplast genome encodes 106 genes: 72 protein-coding genes, 30 tRNAs, and 4 rRNAs. The phylogenetic analysis result strongly suggested that M. archiducis-nicolai is a distinct lineage in Medicago, being sister to highly supported clade composed of three species (M. hybrida, M. papillosa and M. sativa).

Analyzing the Carotenoid Composition of Melilot (Melilotus officinalis (L.) Pall.) Extracts and the Effects of Isolated (All-E)-lutein-5,6-epoxide on Primary Sensory Neurons and Macrophages

Melilotus officinalis is known to contain several types of secondary metabolites. In contrast, the carotenoid composition of this medicinal plant has not been investigated, although it may also contribute to the biological activities of the drug, such as anti-inflammatory effects. Therefore, this study focuses on the isolation and identification of carotenoids from Meliloti herba and on the effect of isolated (all-E)-lutein 5,6-epoxide on primary sensory neurons and macrophages involved in nociception, as well as neurogenic and non-neurogenic inflammatory processes. The composition of the plant extracts was analyzed by high performance liquid chromatography (HPLC). The main carotenoid was isolated by column liquid chromatography (CLC) and identified by MS and NMR. The effect of water-soluble lutein 5,6-epoxide-RAMEB (randomly methylated-β-cyclodextrin) was investigated on Ca²⁺-influx in rat primary sensory neurons induced by the activation of the transient receptor potential ankyrin 1 receptor agonist to mustard-oil and on endotoxin-induced IL-1β release from isolated mouse peritoneal macrophages. (all-E)-Lutein 5,6-epoxide significantly decreased the percent of responsive primary sensory neurons compared to the vehicle-treated stimulated control. Furthermore, endotoxin-evoked IL-1β release from macrophages was significantly decreased by 100 µM lutein 5,6-epoxide compared to the vehicle-treated control. The water-soluble form of lutein 5,6-epoxide-RAMEB decreases the activation of primary sensory neurons and macrophages, which opens perspectives for its analgesic and anti-inflammatory applications.

The complete chloroplast genome sequence of Lotus corniculatus L

Lotus corniculatus L., a member of the Fabaceae family, is considered one of the most agriculturally important forage plants, owing to its anti-bloating properties; its ability to grow in low-fertility, acidic, and high-salinity soils; and high nutritional value. In this study, we obtained the complete chloroplast genome of L. corniculatus by Illumina sequencing and GetOrganelle assembly pipeline. The whole chloroplast genome of L. corniculatus is 150,700 bp in length, and has a typical circular structure with four parts: a large single-copy region (LSC 82,117 bp), a small single-copy region (SSC 18,275 bp), and a pair of inverted repeat regions (25,154 bp for both IRa and IRb). The overall GC content is 36.03%. The plastome has 109 unique genes, consisting of 78 protein-coding genes, 27 unique tRNA gene, and 4 unique rRNA genes. Based on the protein-coding gene sequences from 17 species, we reconstructed a maximum likelihood (ML) tree. The phylogenetic result shows that L. corniculatus has a closer relationship with Lotus japonicas.

A review on genus Millettia: Traditional uses, phytochemicals and pharmacological activities

The genus Millettia belongs to Fabaceae includes 200 species which are distributed in tropical and subtropical regions of the world. Plants belong to this genus are used as folkloric medicine, for the treatment of different ailments like in wound healing, boil, sores, skin diseases, snake bite, muscle aches, pains, rheumatic arthritis, and gynaecological diseases. The aim of the review is to provide updated, comprehensive and categorized information on the aspects of ethnobotanical, phytochemical, pharmacological uses and toxicity of genus Millettia in order to identify their therapeutic potential and generate space for future research opportunities. The present study comprises of isolated flavonoids, phenolic compounds, phytosterols, saponins, alkaloids, polysaccharides, terpenoids and resins and pharmacological activities of various Millettia species. The relevant data were searched by using the keyword “Millettia” in different scientific databases like, “Google Scholar”; “NISCAIR repository”; “Pub Med”; “Science Direct”; “Scopus” and the taxonomy is validated by “The Plant List”. This review discusses the existing information of the traditional evaluation as well as phytochemical and pharmacological evaluation of the extract and active constituents of the genus “Millettia”. This review confirms that several Millettia species have emerged as a high-quality medicine in a traditional system for arthritis, wound healing, inflammation, skin diseases. Numerous conventional uses of Millettia species have been validated by modern pharmacology research. Intensive investigations of the genus Millettia relating to phytochemistry and pharmacology, especially their mechanism of action, safety, and efficacy could be the future research interests by the researcher in the area of phytomedicine.

Poincianella pyramidalis (Tul) L.P. Queiroz: A review on traditional uses, phytochemistry and biological-pharmacological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Poincianella pyramidalis (Tul.) LP Queiroz (Fabaceae) is an endemic tree in the Northeast of Brazil. Its flowers, leaves, stem bark and root have been used over the years to treat infections, abdominal pain, inflammation, diarrhea, heartburn, and dyspepsia.

AIM OF THE STUDY

The present study is a critical assessment of the state-of-the-art concerning traditional uses, phytochemistry, pharmacology and toxicology of P. pyramidalis performed through the application of a robust research strategy to explore the therapeutic potential of P. pyramidalis extracts and isolated compounds for the treatment of human disorders.

MATERIALS AND METHODS

Information related to this review was systematically collected from scientific literature databases for P. pyramidalis, including papers and patents (PubMed, Science Direct, Scopus, Web of Science, Google scholar, INPI, WIPO, EPO and USPTO), published books (e.g. Plantas Forrageiras das Caatingas), dissertations and theses. Plant taxonomy has been confirmed in the "The Plant List" database (www.theplantlist.org).

RESULTS

Phytochemical analysis of P. pyramidalis shows several constituents such as flavonoids, triterpenoids and phenylpropanoids. The extract and isolated constituents exhibited a wide range of in vitro and in vivo pharmacological effects including antimicrobial, antinociceptive, anti-inflammatory, gastroprotective and neuroprotective activities. In addition, toxicity studies showed that the administration of P. pyramidalis extract was safe in non-pregnant rats but displayed teratogenic effects in rats and goats. On the other hand, the search in patent databases reported a single filing, which highlights the disparity between a large number of published scientific articles versus the almost nonexistent filing of patents. This fact evidences a still little explored technological potential of the species.

CONCLUSION

P. pyramidalis represents an important therapeutic resource for the population from the Northeast of Brazil. Pharmacological studies confirmed the effectiveness of the extract or isolated compounds in the treatment of various pathologies traditionally treated with P. pyramidalis. The authors emphasize the need for in-depth research and future clinical trials in order to investigate the clinical efficacy and safety of P. pyramidalis.

Complete chloroplast genome of a high-quality forage in north China, Medicago ruthenica (Fabaceae：Trifolieae)

Medicago ruthenica is a well-known high-quality forage due to its good palatability and strong tolerance to drought, cold and saline-alkali stress. Here, the complete chloroplast genome sequence of M. ruthenica was reported. The chloroplast genome is 126,939 bp in length. This chloroplast genome has no inverted repeat (IR) regions, which is very common in the family Fabaceae. The M. ruthenica chloroplast genome encodes 107 genes, including 73 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Phylogenetic analysis result strongly suggested that M. ruthenica is a distinct lineage in Medicago, being sister to highly supported clade composed of three species (M. hybrida, M. papillosa and M. sativa).

Bioassay-guided Isolation of Flavonoids from Caesalpinia bonduc (L.) Roxb. and Evaluation of Their Cytotoxicity

Cancer is one of the most important causes of death all around the world. Screening plants and their secondary metabolites as cytotoxic agents is one of the common methods for identifying new compounds used in chemotherapy and inhibition cancer process. Caesalpinia bonduc (L.) Roxb. from the Fabaceae family was used for improving wound, fever, tumor, hydrocele, hernia, smallpox, toothache, inflammation, and as astringent, anthelmintic, antidiabetic, and antimalarial agent in traditional medicine. A bioassay-guided study of this species led to the isolation of three flavonoids. At first, the cytotoxicity of methanol extract of aerial parts (leaves and stems), seeds, and legumes of this plant was tested against MCF-7 and PC-3 by MTT assay. The methanol extract of legumes showed better inhibitory activities (IC50 < 500 µg/mL). As a result, this extract was selected for fractionation. In the next step, the ethyl acetate (EtOAc) fraction was selected for phytochemical analysis based on the inhibitory activity (IC50 = 170 ± 0.9 µg/mL). In this way, total phenol content (625 ± 7.2 GAE/g extract) and antioxidant activity (IC50 = 6.1 ± 0.3 µg/mL) was compared by BHT (IC50 = 13.5 ± 0.7 µg/mL). Finally, three compounds including, quercetin-3-methyl ether (1), kaempferol (2), and kaempferol-3-O-α-L-rhamnopyranosyl-1→2)-β-D-xylopyranoside (3) were isolated from EtOAc fraction, and all isolated compounds were tested for their cytotoxicity and compound 1 showed better inhibitory activity than other two compounds. This study suggests that Caesalpinia bonduc could be considered for further investigations as a natural source of biological compounds.

The regression of endometriosis with glycosylated flavonoids isolated from Melilotus officinalis (L.) Pall. in an endometriosis rat model

OBJECTIVE

Melilotus officinalis (L.) Pall. is commonly used for treating bronchitis, painful menstruation, hemorrhoids, kidney stones, ulcers of the eyes, earache, and hardening and swelling of uterus. The European Medicines Agency reported the use of M. officinalis orally against stomach ache, gastric ulcer, and disorders of the liver and uterus in folk medicine. The present study aimed to appraise the activity of M. (L.) Pall. aerial parts in endometriosis rat model.

MATERIALS AND METHODS

The endometriosis rat model was used to evaluate the potential activity of M. officinalis aerial parts based on its folkloric usage. The aerial parts of M. officinalis were extracted with n-hexane, ethyl acetate (EtOAc), and methanol (MeOH), respectively. The adhesion scores, endometrial foci areas, and cytokine levels were measured in all treated groups. After the biological activity studies, phytochemical studies were performed on the active extract and the fractions obtained from the active extract.

RESULTS

The MeOH extract significantly decreased the endometrial foci areas and cytokine levels in rats with endometriosis. Fractionation was performed on the MeOH extract to achieve bioactive molecules. Following the fractionation, the fractions obtained from the MeOH extract were tested. Fraction C showed the highest activity in the rat endometriosis model. Phytochemical investigation of the active fraction (Fraction C) resulted in isolation and elucidation of some quercetin and kaempferol glucoside derivatives.

CONCLUSION

Fraction C obtained from the MeOH extract of M. officinalis showed the highest activity, yielding four glycosylated flavonoids.

Hybrid capture of 964 nuclear genes resolves evolutionary relationships in the mimosoid legumes and reveals the polytomous origins of a large pantropical radiation

PREMISE

Targeted enrichment methods facilitate sequencing of hundreds of nuclear loci to enhance phylogenetic resolution and elucidate why some parts of the "tree of life" are difficult (if not impossible) to resolve. The mimosoid legumes are a prominent pantropical clade of ~3300 species of woody angiosperms for which previous phylogenies have shown extensive lack of resolution, especially among the species-rich and taxonomically challenging ingoids.

METHODS

We generated transcriptomes to select low-copy nuclear genes, enrich these via hybrid capture for representative species of most mimosoid genera, and analyze the resulting data using de novo assembly and various phylogenomic tools for species tree inference. We also evaluate gene tree support and conflict for key internodes and use phylogenetic network analysis to investigate phylogenetic signal across the ingoids.

RESULTS

Our selection of 964 nuclear genes greatly improves phylogenetic resolution across the mimosoid phylogeny and shows that the ingoid clade can be resolved into several well-supported clades. However, nearly all loci show lack of phylogenetic signal for some of the deeper internodes within the ingoids.

CONCLUSIONS

Lack of resolution in the ingoid clade is most likely the result of hyperfast diversification, potentially causing a hard polytomy of six or seven lineages. The gene set for targeted sequencing presented here offers great potential to further enhance the phylogeny of mimosoids and the wider Caesalpinioideae with denser taxon sampling, to provide a framework for taxonomic reclassification, and to study the ingoid radiation.

Anti-proliferative cassane-type diterpenoids from the seeds of Caesalpinia minax

The seeds of Caesalpinia minax Hance have shown anti-tumor potential, while the chemical principle is still unknown. In a search for anti-tumor compounds, six new cassane-type diterpenoids, 12-demethylcaesalpin G (1), caesalpinolide H (2), 12-demethylcaesalpin H (3), caesalpinolide J (4), 12-O-ethyl neocaesalpin B (5), and 3-deacetyldecapetpene B (6), were isolated from the seeds of C. minax Hance, along with fifteen known analogues. The structures of the new compounds were established by means of spectroscopic techniques (NMR, HRESIMS and IR). The absolute configurations of the new compounds were determined by their ECD spectra. All of the new compounds were tested for their anti-proliferative activity against human lung cancer A549 cells, breast cancer MCF-7 cells, and ovarian cancer HEY cells. The results indicated that only compound 6 displayed moderate cytotoxicity against three cancer cell lines. Thus, the opening of furan ring in cassane-type diterpenoids might enhance the cytotoxic activity.

Inhibitory effect of Newtonia extracts and myricetin-3-o-rhamnoside (myricitrin) on bacterial biofilm formation

BACKGROUND

Diarrhoea is a major health issue in both humans and animals and may be caused by bacterial, viral and fungal infections. Previous studies highlighted excellent activity of Newtonia buchananii and N. hildebrandtii leaf extracts against bacterial and fungal organisms related to diarrhoea-causing pathogens. The aim of this study was to isolate the compound(s) responsible for antimicrobial activity and to investigate efficacy of the extracts and purified compound against bacterial biofilms.

METHODS

The acetone extract of N. buchananii leaf powder was separated by solvent-solvent partitioning into eight fractions, followed by bioassay-guided fractionation for isolation of antimicrobial compounds. Antibacterial activity testing was performed using a broth microdilution assay. The cytotoxicity was evaluated against Vero cells using a colorimetric MTT assay. A crystal violet method was employed to test the inhibitory effect of acetone, methanol: dichloromethane and water (cold and hot) extracts of N. buchananii and N. hildebrandtii leaves and the purified compound on biofilm formation of Pseudomonas aeruginosa, Escherichia coli, Salmonella Typhimurium, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus.

RESULTS

Myricetin-3-o-rhamnoside (myricitrin) was isolated for the first time from N. buchananii. Myricitrin was active against B. cereus, E. coli and S. aureus (MIC = 62.5 μg/ml in all cases). Additionally, myricitrin had relatively low cytotoxicity with IC₅₀ = 104 μg/ml. Extracts of both plant species had stronger biofilm inhibitory activity against Gram-positive than Gram-negative bacteria. The most sensitive bacterial strains were E. faecalis and S. aureus. The cold and hot water leaf extracts of N. buchananii had antibacterial activity and were relatively non-cytotoxic with selectivity index values of 1.98-11.44.

CONCLUSIONS

The purified compound, myricitrin, contributed to the activity of N. buchananii but it is likely that synergistic effects play a role in the antibacterial and antibiofilm efficacy of the plant extract. The cold and hot water leaf extracts of N. buchananii may be developed as potential antibacterial and antibiofilm agents in the natural treatment of gastrointestinal disorders including diarrhoea in both human and veterinary medicine.

Antimicrobial peptides in the seedling transcriptome of the tree legume Peltophorum dubium

Antimicrobial peptides (AMPs) play an essential role in plant defense against invading pathogens. Due to their biological properties, these molecules have been considered useful for drug development, as novel agents in disease therapeutics, applicable to both agriculture and medicine. New technologies of massive sequencing open opportunities to discover novel AMP encoding genes in wild plant species. This work aimed to identify cysteine-rich AMPs from Peltophorum dubium, a legume tree from South America. We performed whole-transcriptome sequencing of P. dubium seedlings followed by de novo transcriptome assembly, uncovering 78 AMP transcripts classified into five families: hevein-like, lipid-transfer proteins (LTPs), alpha hairpinins, defensins, and snakin/GASA (Giberellic Acid Stimulated in Arabidopsis) peptides. No transcripts with similarity to cyclotide or thionin genes were identified. Genomic DNA analysis by PCR confirmed the presence of 18 genes encoding six putative defensins and 12 snakin/GASA peptides and allowed the characterization of their exon-intron structure. The present work demonstrates that AMP prediction from a wild species is possible using RNA sequencing and de novo transcriptome assembly, regarding a starting point for studies focused on AMP gene evolution and expression. Moreover, this study allowed the detection of strong AMP candidates for drug development and novel biotechnological products.

The complete chloroplast genome sequence of medicinal plant: Astragalus laxmannii (Fabaceae)

Astragalus laxmannii is a traditional Chinese medicine. The complete chloroplast genome sequence is 122,844 bp in length, contains 110 complete genes, including 75 protein-coding genes (75 PCGs), 8 ribosomal RNA genes (4 rRNAs), and 30 tRNA genes (30 tRNAs). The overall GC content of cp DNA is 34.1%. Phylogenetic tree shows that A. laxmannii is a sister to A. strictus.