Antiarthritic potential of the butanol fraction of Sesuvium sesuvioides: An in vitro, in vivo, and in silico evaluation

Sesuvium sesuvioides (Fenzl) Verdc (Aizoaceae) has been traditionally used in the treatment of inflammation, arthritis, and gout. However, its antiarthritic potential has not been evaluated scientifically. The current study was designed to assess the antiarthritic properties of the n-butanol fraction of S. sesuvioides (SsBu) by phytochemical analysis, in vitro and in vivo pharmacological activities, and in silico studies. Phytochemical analysis showed total phenolic contents (90.7 ± 3.02 mg GAE/g) and total flavonoid contents (23.7 ± 0.69 mg RE/g), and further analysis by GC-MS identified possible bioactive phytocompounds belonging to phenols, flavonoids, steroids, and fatty acids. The in vitro antioxidant potential of SsBu was assessed by DPPH (175.5 ± 7.35 mg TE/g), ABTS (391.6 ± 17.1 mg TE/g), FRAP (418.2 ± 10.8 mg TE/g), CUPRAC (884.8 ± 7.97 mg TE/g), phosphomolybdenum (5.7 ± 0.33 mmol TE/g), and metal chelating activity (9.04 ± 0.58 mg EDTAE/g). Moreover, in the in vitro studies, inhibition (%) of egg albumin and bovine serum albumin denaturation assays showed that the anti-inflammatory effect of SsBu at the dose of 800 μg/ml was comparable to that of diclofenac sodium used as a standard drug. The in vivo antiarthritic activity was assessed to determine the curative impact of SsBu against formalin-induced (dose-dependent significant (p < 0.05) effect 72.2% inhibition at 750 mg/kg compared to standard; 69.1% inhibition) and complete Freund's adjuvant-induced arthritis (40.8%; inhibition compared to standard, 42.3%). SsBu significantly controlled PGE-2 level compared to the control group (p < 0.001) and restored the hematological parameters in rheumatoid arthritis. Treatment with SsBu significantly reduced oxidative stress by reinstating superoxide dismutase, GSH, and malondialdehyde along with pro-inflammatory markers (IL-6 and TNF-α) in arthritic rats. Molecular docking revealed the antiarthritic role of major identified compounds. Kaempferol-3-rutinoside was found to be more potent for COX-1 (-9.2 kcal/mol) and COX-2 inhibition (-9.9 kcal/mol) than diclofenac sodium (COX-1, -8.0 and COX-2, -6.5 kcal/mol). Out of the 12 docked compounds, two for COX-1 and seven for COX-2 inhibition showed more potent binding than the standard drug. The results from the in vitro, in vivo, and in silico approaches finally concluded that the n-butanol fraction of S. sesuvioides had antioxidant and antiarthritic potential, which may be due to the presence of potential bioactive compounds.

Indigenous Uses, Phytochemical Analysis, and Anti-Inflammatory Properties of Australian Tropical Medicinal Plants

Australian tropical plants have been a rich source of food (bush food) and medicine to the first Australians (Aboriginal people), who are believed to have lived for more than 50,000 years. Plants such as spreading sneezeweed (Centipeda minima), goat’s foot (Ipomoea pes-caprae), and hop bush (Dodonaea viscosa and D. polyandra) are a few popular Aboriginal medicinal plants. Thus far, more than 900 medicinal plants have been recorded in the tropical region alone, and many of them are associated with diverse ethnomedicinal uses that belong to the traditional owners of Aboriginal people. In our effort to find anti-inflammatory lead compounds in collaboration with Aboriginal communities from their medicinal plants, we reviewed 78 medicinal plants used against various inflammation and inflammatory-related conditions by Aboriginal people. Out of those 78 species, we have included only 45 species whose crude extracts or isolated pure compounds showed anti-inflammatory properties. Upon investigating compounds isolated from 40 species (for five species, only crude extracts were studied), 83 compounds were associated with various anti-inflammatory properties. Alphitolic acid, Betulinic acid, Malabaric acid, and Hispidulin reduced proinflammatory cytokines and cyclooxygenase enzymes (COX-1 and 2) with IC₅₀ values ranging from 11.5 to 46.9 uM. Other promising anti-inflammatory compounds are Brevilin A (from Centipeda minima), Eupalestin, and 5′-methoxy nobiletin (from Ageratum conyzoides), Calophyllolide (from Calophyllum inophyllum), and Brusatol (from Brucea javanica). D. polyandra is one example of an Aboriginal medicinal plant from which a novel anti-inflammatory benzoyl ester clerodane diterpenoid compound was obtained (compound name not disclosed), and it is in the development of topical medicines for inflammatory skin diseases. Medicinal plants in the tropics and those associated with indigenous knowledge of Aboriginal people could be a potential alternative source of novel anti-inflammatory therapeutics.

Composition, Antivirulence Activity, and Active Property Distribution of the Fruit of Terminalia chebula Retz

The fruit of Terminalia chebula Retz., or Tibet Olive, is widely used as a food supplement in China. It possesses some natural antimicrobial properties; however, its chemical composition and antivirulence effects have not been identified. In this work, 29 compounds were identified from the peel of T. chebula fruit by ultra-high-performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry. Both the extract of T. chebula and its phenolic acid, corilagin, showed antivirulent activity against Staphylococcus aureus. Specifically, they inhibited biofilm formation. The half maximal inhibitory concentration was 0.13 and 3.18 µg/mL for the extract and corilagin, respectively, whereas for α-hemolysin secretion, the respective concentrations were 30 and 10 µg/mL. Its mechanism of action may be due to reducing the transcription of genes related to quorum sensing. These genes included staphylococcal accessory regulator A, intercellular adhesion accessory gene regulator A, and RNAIII. These findings provide evidence that this food supplement could be an effective antivirulent with corilagin as its active ingredient. PRACTICAL APPLICATION: Corilagin from the fruit of Terminalia chebula Retz. may be used as an antibacterial for its antivirulent activity against Staphylococcus aureus.