Anti-inflammatory 12,20-Epoxypregnane and 11,12-seco-Pregnane Glycosides from the Stems of Hoya kerrii

Pharmacological properties of Hoya (Apocynaceae): a systematic review

In tropical forests, Hoya, a plant with significant indigenous medicinal applications, has been underexplored in pharmacological studies. This systematic review meticulously investigates the diverse pharmacological effects exhibited by various Hoya species on human health. A comprehensive literature search, encompassing Scopus, ScienceDirect, and SpringerLink databases, employed specific keyword combinations ('Hoya' and 'pharmacological properties' OR 'pharmacology property'). The included studies exclusively focused on Hoya's impact on human health. The findings underscore Hoya's potential as a medicinal plant, demonstrating promising attributes such as anticancer, antibacterial, antioxidant, anti-inflammatory, anti-diabetic, antinociceptive, and parasympatholytic effects. Despite these promising indications, the review underscores the necessity for further in vivo investigations to fully unlock Hoya's therapeutic potential. A comprehensive understanding of its mechanisms of action, efficacy, and safety in living systems is imperative for realising its holistic therapeutic benefits.

Three new minor steroidal glycosides from the whole plants of Hoya parasitica (Wall. ex Hornem.) Wight

Three new minor steroidal glycosides were isolated from the whole plants of Hoya parasitica (Wall. ex Hornem.) Wight. Their structures were further elucidated as 3β,4α-dihydroxy-5β-spirost-(25)27-en-1β-yl O-α-L-arabinopyranoside (1), 3β-hydroxy-5β-spirost-25(27)-en-1β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (2), and (23S,24S,25S)-3β,4α,23,24-tetrahydroxy-5β-spirostan-1β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranoside (3) through interpretation of the spectroscopic data (one-dimensional and two-dimensional) and mass spectrometry (HR-ESI-MS). To the best of our knowledge, this is the first report of the isolation of spirostane-type steroidal saponins from the Hoya genus.

12,20-Epoxypregnane Glycosides from the Roots of Oxypetalum caeruleum

The MeOH extract from dried roots of Oxypetalum caeruleum (Apocynaceae, formerly known as Asclepiadaceae) plants yielded twenty new pregnane glycosides, some of which had a new 12,20-epoxy type aglycone. The structures of these compounds were established using NMR, MS spectroscopic analysis and chemical evidence.

Synthesis, in silico, and in vivo anti-inflammatory evaluation of 3β-cinnamoyloxy substituted pregna-4,16-diene-6,20-diones derivatives

Pregnane derivatives have been studied mainly for their 5α-reductase activity. However, the anti-inflammatory activities of such compounds are still poorly explored. In the search for new anti-inflammatory agents, seven new pregnane derivatives 6a-g, with cinnamic acid esters at C-3 were prepared and fully characterized. The anti-inflammatory activity of compounds was assessed in TPA induced mice ear model. From them, compound 6 b was the most active to reduce edema, with an ED₅₀ of 0.017 mg/ear. Also, Molecular Docking and Molecular Dynamics studies were performed to identify a potential molecular target related to the inflammatory process. The in vivo results suggest that 6 b could be a potent anti-inflammatory compound, while in silico studies suggest its interaction with some critical enzymes in the inflammatory response.

Therapeutic potential of russelioside B as anti-arthritic agent in Freund's adjuvant-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Caralluma species are traditional edible herbs used in folkloric medicine as antidiabetic, antioxidant, antipyretic, antirheumatic, anti-inflammatory and anthelmintic agents. C. quadrangula was selected in this study to document the traditional use of the genus as anti-rheumatic treatment and the possible mechanisms of action.

AIM OF THE STUDY

The higher mortality rates and shorter survival among the patients suffering from rheumatoid arthritis (RA) led to the increased interest on searching for new treatments for RA. Russelioside B (RB), a major pregnane glycoside found in C. quadrangula, was evaluated as a new anti-rheumatic agent.

MATERIALS AND METHODS

The n-butanol fraction of C. quadrangula was chromatographed on a silica gel column to isolate RB. The adjuvant-induced arthritis (AIA) model was established in rats by intradermal injection of complete Freund's adjuvant (CFA) to evaluate its anti-arthritic effect. Ibuprofen was used as a reference drug. Forty rats were randomly divided into 5 groups (n = 8): normal (NOR); CFA model (CFA); ibuprofen, 5 mg/kg; RB, 25 mg/kg and RB, 50 mg/kg. The treatments were initiated from day 16 when AIA model was established and continued up to day 40. Serum diagnostic rheumatoid markers, inflammatory cytokines, oxidative stress biomarkers, cartilage and bone degeneration enzymes were assessed.

RESULTS

RB at 50 mg/kg b. wt., showed significant decreases in the activities of hyaluronidase and β-glucouronidase enzymes as well significant decreases in the levels of proinflammatory cytokines as nuclear factor-kappa-B (NF-κB), tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) compared to the CFA group; 11.04 ± 0.61 pg/mg protein, 4.35 ± 0.25 pg/mg protein, 3.32 ± 0.13 pg/mg protein & 2.75 ± 0.14 pg/mg protein for RB, 50 mg/kg b. wt. group vs. 25.33 ± 2.13 pg/mg protein, 25.65 ± 2.1 pg/mg protein, 22.20 ± 1.34 pg/mg protein & 13.27 ± 1.40 pg/mg protein for the arthritic group, respectively. The total antioxidant capacity (TAC) was significantly restored to normal values in RB, 50 mg/kg treated rats (4.01 ± 0.09 nmol/mL vs. 3.71 ± 0.27 nmol/mL) and the levels of myeloperoxidase (MPO) reduced by 10-folds of the CFA arthritic group. Bone histomorphometry revealed that RB treatment significantly attenuated the CFA-induced bone loss in a dose-dependent manner.

CONCLUSIONS

These findings suggested that the anti-arthritic effect of RB was mediated through the reduction of the rheumatoid markers, anti-inflammatory and antioxidant action, inhibition of cartilage and bone degenerative enzymes as well as attenuation of bone loss and osteoclastogenesis.

Unraveling Plant Natural Chemical Diversity for Drug Discovery Purposes

The screening and testing of extracts against a variety of pharmacological targets in order to benefit from the immense natural chemical diversity is a concern in many laboratories worldwide. And several successes have been recorded in finding new actives in natural products, some of which have become new drugs or new sources of inspiration for drugs. But in view of the vast amount of research on the subject, it is surprising that not more drug candidates were found. In our view, it is fundamental to reflect upon the approaches of such drug discovery programs and the technical processes that are used, along with their inherent difficulties and biases. Based on an extensive survey of recent publications, we discuss the origin and the variety of natural chemical diversity as well as the strategies to having the potential to embrace this diversity. It seemed to us that some of the difficulties of the area could be related with the technical approaches that are used, so the present review begins with synthetizing some of the more used discovery strategies, exemplifying some key points, in order to address some of their limitations. It appears that one of the challenges of natural product-based drug discovery programs should be an easier access to renewable sources of plant-derived products. Maximizing the use of the data together with the exploration of chemical diversity while working on reasonable supply of natural product-based entities could be a way to answer this challenge. We suggested alternative ways to access and explore part of this chemical diversity with in vitro cultures. We also reinforced how important it was organizing and making available this worldwide knowledge in an "inventory" of natural products and their sources. And finally, we focused on strategies based on synthetic biology and syntheses that allow reaching industrial scale supply. Approaches based on the opportunities lying in untapped natural plant chemical diversity are also considered.

Mannosylxylarinolide, a new 3,4-seco-ergostane-type steroidal saponin featuring a β-d-mannose from the endophytic fungus Xylaria sp

Mannosylxylarinolide (1), a new 3,4-seco-ergostane-type steroidal saponin featuring a β-d-mannose moiety, was isolated from the culture of the endophytic fungus Xylaria sp. that had been isolated from an ornamental plant of Hoya sp. The gross structure was determined by spectroscopic data, and the absolute configuration of the new 3,4-seco-ergostane-type steroidal saponin (1) was determined by X-ray diffraction analysis.

Cytotoxic Pregnane Steroidal Glycosides from Chonemorpha megacalyx

Three new C₂₁ pregnane steroids, chonemorphols A-C (1, 3, and 4), 11 new C₂₁ steroidal glycosides, chonemorphosides A-K (2 and 5-14), and 11 known compounds (15-25) were obtained from the vines and leaves of Chonemorpha megacalyx Pierre. Their structures were established using extensive spectroscopic data. The X-ray crystallographic data of 1 and 3 permitted definition of their absolute configurations. Notably, 1 and 2 possessed an uncommon 6/5/6/5/5-fused steroidal ring system. Compound 7 displayed significant cytotoxicity against several cancer cell lines with IC₅₀ values of 2.0-3.6 μM.

Human disorders associated with inflammation and the evolving role of natural products to overcome

Inflammation is a biological function which triggered after the mechanical tissue disruption or from the responses by the incidence of physical, chemical or biological negotiator in body. These responses are essential act provided by the immune system during infection and tissue injury to maintain normal tissue homeostasis. Inflammation is a quite complicated process at molecular level with the involvement of several proinflammatory expressions. Several health problems are associated with prolonged inflammation, which effects nearly all major to minor diseases. The molecular and epidemiological studies jagged that the inflammation is closely associated with several disorders with their specific targets. It would be great achievement for human health around the world to overcome on inflammation. Mostly used anti-inflammatory drugs are at high risk of side effects and also expensive. Hence, the plant-based formulations gained a wide acceptance by the public and medical experts to treat it. Due to extensive dispersal, chemical diversity and systematically established biological potentials of natural products have induced renewed awareness as a gifted source for medications. However, today's urgent need to search for cheaper, more potent and safe anti-inflammatory medications to overcome on current situation. The goal of this review to compile an update on inflammation, associated diseases, molecular targets, inflammatory mediators and role of natural products. The entire text concise the involvement of various cytokines in pathogenesis of various human disorders. This assignment discussed about 321 natural products with their promising anti-inflammatory potential discovered during January 2009 to December 2018 with 262 citations.

Up-regulation of COX-2 and mPGES-1 by 27-hydroxycholesterol and 4-hydroxynonenal: A crucial role in atherosclerotic plaque instability

Atherosclerosis is currently understood to be mainly the consequence of a complicated inflammatory process at the different stages of plaque development. Among the several inflammatory molecules involved, up-regulation of the functional cyclooxygenase 2/membrane-bound prostaglandin E synthase 1 (COX-2/mPGES-1) axis plays a key role in plaque development. Excessive production of oxidized lipids, following low-density lipoprotein (LDL) oxidation, is a characteristic feature of atherosclerosis. Among the oxidized lipids of LDLs, the oxysterol 27-hydroxycholesterol (27-OH) and the aldehyde 4-hydroxynonenal (HNE) substantially accumulate in the atherosclerotic plaque, contributing to its progression and instability through a variety of processes. This study shows that 27-OH and HNE promote up-regulation of both the inducible enzymes COX-2 and mPGES-1, leading to increased production of prostaglandin (PG) E₂ and inducible nitric oxide synthase, and the subsequent release of nitric oxide in human promonocytic U937 cells. The study also examined the potential involvement of the functionally coupled COX-2/mPGES-1 in enhancing the production of certain pro-inflammatory cytokines and of matrix metalloproteinase 9 by U937 cells. This enhancement is presumably due to the induction of PGE₂ synthesis, as a result of the up-regulation of the COX-2/mPGES-1, stimulated by the two oxidized lipids, 27-OH and HNE. Induction of PGE₂ synthesis might thus be a mechanism of plaque instability and eventual rupture, contributing to matrix metalloproteinase production by activated macrophages.