Lignans from guaiac resin decrease nitric oxide production in interleukin 1β-treated hepatocytes

The synergistic effects of Guaiacum officinale and Rhodomyrtus tomentosa extracts in the treatment of acne vulgaris on sensitive skin

BACKGROUND

Acne vulgaris, a common chronic dermatological condition worldwide, is associated with inflammatory response and Cutibacterium acnes. Individuals with acne vulgaris and sensitive skin have limited suitable treatments due to the skin irritation and side effects exhibited by current hydroxy acidic medications.

AIMS

This study aimed to evaluate the synergistic effects of Guaiacum officinale (GO) and Rhodomyrtus Tomentosa (RT) extracts for treating acne vulgaris on sensitive skin by inhibiting inflammation.

METHODS

The phytochemical constituents and antioxidant activity of GO and RT extracts were determined in vitro. The anti-inflammatory effects were investigated in peptidoglycan (PGN)-induced HaCaT cells. Further, a 28-day clinical trial was conducted involving 30 subjects with both sensitive skin and acne to evaluate the efficacy and subjects' satisfaction.

RESULTS

Total phenolics and flavonoids were detected in GO and RT extracts, the IC50 values for DPPH radical scavenging were 6.15 wt% and 0.76 wt%, respectively. The combination of GO and RT extracts at a 1:1 (v/v) ratio significantly decreased the expression of TLR-2 and TLR-4, as well as the secretion of IL-1α, IL-8, and TNF-α in PGN-induced HaCaT cells, by 2.30-7.93 times compared to GO extract alone (p < 0.05). Moreover, the cream containing 5 wt% the combination significantly improved facial acne and redness (p < 0.05). The number of comedones decreased by 50.00% and papules by 30.65% after 28 days of application. No adverse events were reported and 96.67% of the subjects were satisfied with the treatment.

CONCLUSION

The efficacy of the GO and RT extracts in synergistically suppressing inflammation, improving acne vulgaris, and reducing redness. The study offers an effective and non-irritant treatment for acne vulgaris in individuals with sensitive skin.

Green synthesis of zinc oxide nanoparticles using ethanolic extract of Gliricidia sepium (Jacq.) kunth. Ex. Walp., stem: Characterizations and their gastroprotective effect on ethanol-induced gastritis in rats

The study presents a significant advancement in drug delivery and therapeutic efficacy through the successful synthesis of Gliricidia sepium(Jacq.) Kunth. ex. Walp., stem zinc oxide nanoparticles(GSS ZnONPs). The phenolic compounds present in Gliricidia sepium stem (GSS) particularly vanillic acid, apegnin-7-O-glucoside, syringic acid, and p-coumaric acid which were identified by HPLC. These compounds shown antioxidant and anti-inflammatory properties. GSS ZnONPs demonstrate pronounced gastroprotective effects against ethanol-induced gastritis, evidenced by the reduction in gastric lesions and mucosal injury upon its treatment. Histopathological evaluation and immunohistochemical analysis of nuclear factor erythroid 2-related factor 2 (Nrf2) expression further validate these results, revealing the amelioration of ethanol-induced gastritis and improved gastric tissue condition due to their treatment. Noteworthy is the dose-dependent response of GSS ZnONPs, showcasing their efficacy even at lower doses against ethanol-induced gastritis which is confirmed by different biomarkers. These findings have substantial implications for mitigating dosage-related adverse effects while preserving therapeutic benefits, offering a more favorable treatment approach. This study aims to investigate the potential gastroprotective activity of GSS ZnONPs against gastritis.

Identification of Anti-Inflammatory Compounds from Peucedanum praeruptorum Roots by Using Nitric Oxide-Producing Rat Hepatocytes Stimulated by Interleukin 1β

The roots of Peucedanum praeruptorum Dunn and Angelica decursiva Franchet et Savatier are designated Zenko, which is a crude drug defined by the Japanese Pharmacopoeia. This crude drug is used as an antitussive and an expectorant and is included in the Kampo formula Jinsoin, which improves cough, fever, and headache. Although the anti-inflammatory effects of this crude drug have been determined, the constituents responsible for this effect remain unknown. To investigate biologically active compounds, rat hepatocytes were used, which produce proinflammatory mediator nitric oxide (NO) in response to proinflammatory cytokine interleukin 1β (IL-1β). A methanol extract of P. praeruptorum roots, which suppressed IL-1β-induced NO production, was fractionated into three crude fractions (ethyl acetate (EtOAc)-soluble, n-butanol-soluble, and water-soluble fractions) based on hydrophobicity. The EtOAc-soluble fraction markedly inhibited NO production. After this fraction was purified, three biologically active compounds were identified as praeruptorins A, B, and E, the contents of which were high. A comparison of their activities indicated that praeruptorin B exhibited the highest potency to inhibit NO production by decreasing inducible NO synthase expression and suppressed the expression of mRNAs encoding proinflammatory cytokines. Collectively, the three praeruptorins may primarily contribute to the anti-inflammatory effects of P. praeruptorum roots.

Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Plant lignans exhibit a wide range of biological activities, which makes them the research objects of potential use as therapeutic agents. They provide diverse naturally-occurring pharmacophores and are available for production by chemical synthesis. A large amount of accumulated data indicates that lignans of different structural groups are apt to demonstrate both anti-inflammatory and antioxidant effects, in many cases, simultaneously. In this review, we summarize the comprehensive knowledge about lignan use as a bioactive agent in disorders associated with oxidative stress and inflammation, pharmacological effects in vitro and in vivo, molecular mechanisms underlying these effects, and chemical synthesis approaches. This article provides an up-to-date overview of the current data in this area, available in PubMed, Scopus, and Web of Science databases, screened from 2000 to 2022.

Lignans, Amides, and Saponins from Haplophyllum tuberculatum and Their Antiprotozoal Activity

A screening of Sudanese medicinal plants for antiprotozoal activities revealed that the chloroform and water fractions of the ethanolic root extract of Haplophyllum tuberculatum exhibited appreciable bioactivity against Leishmania donovani. The antileishmanial activity was tracked by HPLC-based activity profiling, and eight compounds were isolated from the chloroform fraction. These included lignans tetrahydrofuroguaiacin B (1), nectandrin B (2), furoguaiaoxidin (7), and 3,3'-dimethoxy-4,4'-dihydroxylignan-9-ol (10), and four cinnamoylphenethyl amides, namely dihydro-feruloyltyramine (5), (E)-N-feruloyltyramine (6), N,N'-diferuloylputrescine (8), and 7'-ethoxy-feruloyltyramine (9). The water fraction yielded steroid saponins 11-13. Compounds 1, 2, and 5-13 are reported for the first time from Haplophyllum species and the family Rutaceae. The antiprotozoal activity of the compounds plus two stereoisomeric tetrahydrofuran lignans-fragransin B2 (3) and fragransin B1 (4)-was determined against Leishmania donovani amastigotes, Plasmodium falciparum, and Trypanosoma brucei rhodesiense bloodstream forms, along with their cytotoxicity to rat myoblast L6 cells. Nectandrin B (2) exhibited the highest activity against L. donovani (IC50 4.5 µM) and the highest selectivity index (25.5).

Isolation and Identification of Lignans and Other Phenolic Constituents from the Stem Bark of Albizia julibrissin Durazz and Evaluation of Their Nitric Oxide Inhibitory Activity

A dibenzylbutane-type lignan (16), along with eight furofuran-type (1–8), five furan-type (9–13), two dibenzylbutane-type (14 and 15), two bibenztetrahydronaphthalene-type lignans (17 and 18), two neolignans (19 and 20), and six phenolic derivatives (21–26) were isolated from an MeOH extract of the stem bark of Albizia julibrissin Durazz. The chemical structures of the obtained compounds were elucidated by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses. Of the evaluated compounds, 14 were isolated from A. julibrissin and the Fabaceae family for the first time. Anti-inflammatory effects of the isolated analogs were investigated in terms of the inhibition of the nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophage cells. Ten compounds (10–12, 14, and 17–22) displayed significant dose-dependent inhibitory effects against the NO production, with IC₅₀ values ranging from 5.4 to 19.2 µM. Moreover, eight compounds (1–4, 9, 13, 15, and 16) exhibited moderate inhibitory activities, with IC₅₀ values ranging from 21.0 to 62.5 µM.

Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances

Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC₅₀ = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC₅₀ = 3.2 nM) and antiviral (patentiflorin A, IC₅₀ = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC₅₀ = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.