Digalloyl Glycoside: A Potential Inhibitor of Trypanosomal PFK from Euphorbia abyssinica J.F. Gmel

Human African trypanosomiasis is an endemic infectious disease caused by Trypanosoma brucei via the bite of tsetse-fly. Most of the drugs used for the treatment, e.g., Suramin, have shown several problems, including the high level of toxicity. Accordingly, the discovery of anti-trypanosomal drugs from natural sources has become an urgent requirement. In our previous study on the anti-trypanosomal potential of Euphorbia species, Euphorbia abyssinica displayed significant anti-trypanosomal activity. Therefore, a phytochemical investigation of the methanolic extract of E. abyssinica was carried out. Twelve compounds, including two triterpenes (1, 2); one sterol-glucoside (4); three ellagic acid derivatives (3, 9, 11); three gallic acid derivatives (5, 6, 10); and three flavonoids (7, 8, 12), were isolated. The structures of isolated compounds were determined through different spectroscopic techniques. Compound (10) was obtained for the first time from genus Euphorbia while all other compounds except compound (4), were firstly reported in E. abyssinica. Consequently, an in silico study was used to estimate the anti-trypanosomal activity of the isolated compounds. Several compounds displayed interesting activity where 1,6-di-O-galloyl-d-glucose (10) appeared as the most potent inhibitor of trypanosomal phosphofructokinase (PFK). Moreover, molecular dynamics (MD) simulations and ADMET calculations were performed for 1,6-di-O-galloyl-d-glucose. In conclusion, 1,6-di-O-galloyl-d-glucose revealed high binding free energy as well as desirable molecular dynamics and pharmacokinetic properties; therefore, it could be suggested for further in vitro and in vivo studies for trypanosomiasis.

Sidastrum paniculatum (L.) Fryxell (Malvaceae): A Promising Source of Bioactive Sulfated Flavonoids Against Aedes aegypti L

Aedes aegypti L. is known as the most relevant vector mosquito for viruses such as yellow fever, chikungunya, dengue, and Zika, especially in places with unplanned urbanization, and erratic water supply. Plants used in folk medicine have become a useful source of active compounds with the potential to control the dissemination of Ae. aegypti. Compounds isolated from Malvaceae sensu lato have been previously reported as larvicides, repellents, and insecticides. Recent studies have demonstrated the anti Ae. aegypti activity of sulfated flavonoids, an uncommon type of flavonoid derivatives. This research reports the phytochemical investigation of Sidastrum paniculatum (L.) Fryxell, a Malvaceae species with the potential against Ae. aegypti. Chromatographic procedures resulted in the isolation of the compounds: stearic acid (1), N-trans-feruloyltyramine (2), acacetin (3), apigenin (4), tiliroside (5), along with the sulfated flavonoids: wissadulin (6), 7,4′-di-O-methyl-8-O-sulfate flavone (7), yannin (8), beltraonin (9a), 7-O-sulfate isoscutellarein (paniculatumin) (9b), and condadin (10). This is the first report of compound 7-O-sulfate isoscutellarein (9b). The structures were elucidated by spectroscopic analysis (NMR, LC-HRMS and FT-IR). The sulfated flavonoids identified were submitted to a ligand-based and structure-based virtual screening against two targets: 1YIY (from adult Ae. aegypti) and 1PZ4 (from Ae. aegypti larvae). The results indicated that when the O-sulfate group is bearing the position 7, the structures are potentially active in 1PZ4 protein. On the other hand, flavonoids with the O-sulfate group bearing position 8 were showed to be more likely to bind to the 1YIY protein. Our findings indicated that S. paniculatum is a promising source of sulfated flavonoids with potential against Ae. aegypti.

Phytochemical and pharmacological investigation of the ethanol extract of Byttneria pilosa Roxb.

Background Traditionally, the herb Byttneria pilosa Roxb. is used for bone fractures, boils, scabies, rheumatalgia, snake bites, syphilis, elephantiasis, poisoning, and eye infection. Scientific reports suggest that it has significant anti-inflammatory, analgesic, anti-diarrheal, anxiolytic, locomotion, sedative and anti-obesity effects. This study aims at the investigation of the phytochemical and pharmacological properties of the ethanol extract of this herb. Methods Fresh whole plant was extracted with absolute ethanol. A preliminary phytochemical investigation was followed by the evaluation of thrombolytic, anti-inflammatory, and anti-nociceptive activities by applying human clotted blood lysis, egg albumin, and acetic acid-induced writhing models, respectively. Results Phytochemical investigation suggests that B. pilosa possesses alkaloids, flavonoids, glycosides, terpenoids, tannins, saponins, and reducing sugars. The extract exhibited clot lysis and anti-inflammatory effects in a concentration-dependent manner. B. pilosa extract at 250 and 500 mg/kg also showed significant (p < 0.05) dose-dependent anti-nociceptive activity in Swiss albino mice. Conclusion The B. pilosa ethanol extract contains many important secondary metabolites and has thrombolytic, anti-inflammatory, and anti-nociceptive activities. More research is necessary on this hopeful medicinal herb.

Steroid, Triterpenoid and Phenylpropanoid From Stereospermum Suaveolens (Roxb.) DC Growing in Bangladesh

The study was carried out to investigate the composition of natural compounds of methanol extract of leaf and stem bark of Stereospermum suaveolens (Roxb.) DC by repeated chromatographic separation and purification processes over silica gel. The phytochemical investigation resulted in the isolation of a total of three compounds, which were identified as stigmasterol (1), β-amyrin (2) and 4-methoxycinnamic acid (3). The chemical structures of the isolated compounds were elucidated by analyses of their physical properties, acquired 1H NMR data and comparison with published reports. Among these, compounds 2 and 3 are first report of their isolation from this plant species. Bangladesh J. Bot. 50(4): 1191-1194, 2021 (December)

Anti-inflammatory Constituents from Caulis Trachelospermi

Caulis Trachelospermi, the stems with leaves of Trachelospermum jasminoides, is a well-known herbal drug of the Apocynaceae family recorded in the Chinese pharmacopeia and used for the treatment of inflammation-related diseases by ethnic minorities of China. The mechanism of anti-inflammatory activity and responsible constituents of T. jasminoides have not been well elucidated in previous studies. Preliminary investigation showed that both the water and the ethyl ester extracts of T. jasminoides exhibited potent inhibitory activity on nitric oxide (NO) production using lipopolysaccharide (LPS)-stimulated murine macrophages. Phytochemical investigation on these extracts afforded 23 compounds, including three new compounds (1 –3) identified on the basis of spectroscopic and mass spectrometric data. Anti-inflammatory bioassay showed that compounds 17, 18, 22, and 23 inhibited significantly the production of NO in a concentration-dependent manner. Further studies indicated that compound 23 inhibited significantly TNF-α and IL-6 produced by LPS-stimulated RAW 264.7 cells with good selectivity, as well as protein expression of iNOS in RAW 264.7 cells. These chemical constituents may contribute to the anti-inflammatory potential of T. jasminoides.

Undescribed C-Glycosylflavones from Corn Silk and Potential Anti-inflammatory Activity Evaluation of Isolates

Phytochemical investigation of corn silk resulted in isolation and characterization of four flavone C-glycosides, chrysoeriol 6-C-β-oliopyranosyl-7-O-β-D-glucopyranoside (1), 3′-methoxycassiaoccidentalin A (2), chrysoeriol 6-C-β-boivinopyranosyl-7-O-β-D-glucopyranoside (3), and ax-4"-OH-3′-methoxymaysin (4), a triterpenoid, friedelin (5), two sterols, (22E)-5,8-epidioxyergosta-6,22-dien-3β-ol (6) and 6β-hydroxystigmasta-4,22-diene-3-one (7), and a mixture of β-sitosterol and stigmasterol. Compounds 1 and 2 were previously undescribed. Structure elucidation of the isolated compounds was attained using spectral data including 1D and 2D NMR and HRESIMS. Compounds 1, 2, 5, and 6 inhibited iNOS activity in LPS-induced macrophages and decreased nitrite levels by 68.64+4.46, 65.67 + 6.47, 88.50 + 0.50, and 94.00 + 4.00 %, respectively, at 50 µM. Compound 5 also showed inhibition of NF-κB (51.00+1.50 %). Compounds 1 and 2 induced NAG-1 activity in chondrocytes by 1.80 + 0.05 and 2.00 + 0.13 fold, respectively. The extract of corn silk, however, did not exhibit inhibition of iNOS or NF-κB but induced NAG-1 by 1.80+ 0.51 fold.

Three New Isoprenylated Flavones from Artocarpus chama Stem and Their Bioactivities

Phytochemical investigation of Artocarpus chama stem was performed by chromatographic techniques, resulting from the isolation and structure elucidation of three new compounds, namely 3′-farnesyl-apigenin (1), 3-(hydroxyprenyl) isoetin (2), and 3-prenyl-5,7,2′,5′-tetrahydroxy-4′-methoxyflavone (3), and five known compounds, namely homoeriodictyol (4), isocycloartobilo-xanthone (5), artocarpanone (6), naringenin (7), and artocarpin (8). From the screening result, A. chama extract showed a potent tyrosinase inhibitory effect. Ihe isolated compounds 1, 4 and 6 also exhibited tyrosinase inhibition with IC50 of 135.70, 52.18, and 38.78 µg/mL, respectively. Moreover, compounds 3, 4, 5, 6, and 8 showed strong activity against Staphylococcus epidermidis, S. aureus, methicillin-resistant S. aureus, and Cutibacterium acnes. This study is the first report on phytochemical investigation with new compounds and biological activities of A. chama. Skin infection can cause dark spots or hyperpigmentation. The isolated compounds that showed both anityrosinase and antimicrobial activities will be further studied in in vivo and clinical trials in order to develop treatment for hyperpigmentation, which is caused by infectious diseases by microorganisms.