Chemical constituents of Miliusa balansae leaves and inhibition of nitric oxide production in lipopolysaccharide-induced RAW 264.7 cells

Antiviral miliusanes and isolation of an unprecedented miliusane dimer from Miliusa balansae

In an extensive screening endeavor for anti-coronaviral compounds, we examined 824 tropical plant extracts from the Annonaceae and Rutaceae families. The screening identified an ethyl acetate extract from the aerial parts of Miliusa balansae for its potent inhibitory activity against Human coronavirus HCoV-229E. Subsequent bioassay-guided fractionation of this extract revealed two unreported miliusanes including a complex dimeric structure and seven known compounds, comprising miliusane XXXVI, (+)-miliusol, bistyryls, styryl-pyranones, and the flavonoid rhamnetin. The absolute configuration of the new dimeric miliusane was determined by X-ray crystallography and a putative biogenetic origin was proposed. Investigation of the antiviral effect of these nine phytochemicals within HCoV-229E-infected Huh-7 cells showed that (+)-miliusol and miliusane XXXVI exert antiviral activity at non-cytotoxic concentrations, with IC50 values of 1.15 μM and 19.20 μM, respectively. Furthermore, these compounds significantly inhibited SARS-CoV-2 infection in Vero cells, presenting IC50 values of 11.31 μM for (+)-miliusol and 17.92 μM for miliusane XXXVI. Additionally, both compounds exhibited a potent antiviral effect against the emergent mosquito-borne Zika virus, with IC50 values of 1.34 μM and 23.45 μM, respectively. Time-of-addition assays suggest that their mechanism of action might target later stages of the viral cycle, indicating potential modulation of specific cellular pathways. These findings reinforce the invaluable contribution of medicinal flora as reservoirs of natural antiviral agents and emphasize their prospective role in combatting viruses of medical interest.

Evaluation of Pharmacological Potential of Miliusa nilagirica Bedd. Leaves Using In Vitro Antidiabetic and Antioxidant Assays

Miliusa nilagirica, a rare tree species of Western Ghats, belongs to the Annonaceae family, a family with potential antioxidant and antidiabetic properties. This study is designed vividly to establish the relationship between the constituent phytochemicals and their hyperglycemic effects through the antioxidant traits of M. nilagirica in vitro. Phytochemical tests were conducted on dry powdered leaves and extracts of various methods to determine the existence of various constituents. The antidiabetic potential of leaf extracts was estimated by using the α-amylase inhibitory model and the antioxidant potential was estimated with various assays. The quantitative phytochemical screening of leaf parts shows the presence of carbohydrates (88.74 ± 0.65 mg GE/g sample), proteins (82.17 ± 2.52 mg BSAE/g sample), phenolics (40.44 ± 0.43 GAE/100 g), and flavonoids (66.05 ± 0.48 mg RE/g extract). Methanol extract of Soxhlet of M. nilagirica registered the strongest antioxidant activity in all assays, 75.66% inhibition (DPPH assay), 795.01 µmol/g (ABTS˙+ radical scavenging), 994.33 µmol/g (FRAP assay), 362.02 mg AAE/g extract (TAC assay), 47% inhibition (NO scavenging assay). In vitro α-amylase inhibition showed a highly noticeable reduction in ethyl acetate extract from Soxhlet (75.19%). HPLC and FTIR analyses on the extracts added strengths to the obtained results on the potentiality of M. nilagirica. From the results, it is evident that phytochemicals from M. nilagirica can be studied further, isolated, and incorporated as an alternative to synthetic supplements for hyperglycemia.

Identification and bioactivity evaluation of miliusanes from Miliusa sinensis

Miliusanes are a class of anticancer lead molecules belonging to meroterpenoids with an 18-carbon skeleton isolated from Miliusa plants. A phytochemical study of the plant M. sinensis was carried out to discover new miliusanes with diverse structural features in order to better understand their structure-activity relationship. As a result, 20 compounds including 12 new ones (7-14 and 17-20) belonging to two sub-classes of miliusanes were isolated and identified from the twigs and leaves of this plant. Their structures, including absolute configurations, were determined by spectroscopic analyses and electronic circular dichroism. The absolute stereochemistry of miliusane structures has also been confirmed for the first time through the single crystal X-ray diffraction analysis of miliusol (1). Bioactivity evaluation showed that some of the miliusane isolates potently inhibit cell growth of several human derived cancer cell lines with IC50 values ranging from 0.52 to 23.5 μM. Compound 11 demonstrated more potent cytotoxic activity than the known miliusol (1) in stomach cancer cells though its structure contains an unconjugated 1, 4-diketone system, which added a new structure-activity feature to miliusanes. The preliminary mechanism of action studies revealed that they could be a class of dual cell migration inhibitor and senescence inducer.

Phytochemical Investigation of Equisetum arvense and Evaluation of Their Anti-Inflammatory Potential in TNFα/INFγ-Stimulated Keratinocytes

Equisetum arvense L. (Equisetaceae), widely known as 'horsetail', is a perennial plant found extensively across Asia. Extracts of E. arvense have been used in traditional medicine, particularly for the treatment of inflammatory disorders. This study aimed to determine the phytochemical compounds in E. arvense ethanolic extract and their anti-inflammatory properties. Subsequently, we isolated and identified nine secondary metabolites, including kaempferol 3,7-di-O-β-D-glucopyranoside (1), icariside B2 (2), (Z)-3-hexenyl β-D-glucopyranoside (3), luteolin 5-O-β-D-glucopyranoside (4), 4-O-β-D-glucopyranosyl caffeic acid (5), clemastanin B (6), 4-O-caffeoylshikimic acid (7), (7S,8S)-threo-7,9,9'-trihydroxy-3,3'-dimethoxy-8-O-4'-neolignan-4-O-β-D-glucopyranoside (8), and 3-O-caffeoylshikimic acid (9). The chemical structures of the isolated compounds (1-9) were elucidated using HR-ESI-MS data, NMR spectra, and ECD data. Next, the anti-inflammatory effects of the isolates were evaluated in tumor necrosis factor (TNF)α/interferon (IFN)γ-induced HaCaT, a human keratinocyte cell line. Among the isolates, compound 3 showed the highest inhibitory effect on the expression of pro-inflammatory chemokines, followed by compounds 6 and 8. Correspondingly, the preceding isolates inhibited TNFα/IFNγ-induced activation of pro-inflammatory transcription factors, signal transducer and activator of transcription 1, and nuclear factor-κB. Collectively, E. arvense could be employed for the development of prophylactic or therapeutic agents for improving dermatitis.

Megastigmane sesquiterpenoids from whole plants of Viola kunawurensis

Investigation on the chemical constituents of Viola kunawurensis resulted in the isolation of seven undescribed megastigmane sesquiterpenoids including four bicyclic megastigmane glucosides, kunawuronoside A-D, two megastigmane glucosides, kunawuronoside E-F, and a megastigmane, kunawurone A, together with ten known megastigmane sesquiterpenoids. Their structures were established by comprehensive 1D, 2D-NMR and HRESIMS analyses, and their absolute configurations were determined by comparing their calculated ECD data with the experimental ones. Evaluations of the anti-inflammatory activity revealed that kunawuronoside A-D and compounds 14-15 inhibited COX-2 expression with inhibition rates ranging from 36.7% to 58.5%, while the NO production induced by lipopolysaccharide (LPS) was suppressed by the kunawuronoside A-D in a dose-dependent manner in RAW264.7 macrophage cell line.

Glycoside constituents from Miliusa sinensis leaves and their anti-inflammatory and acetylcholine protective effects

Repeated column chromatography resulted in the isolation of two new glycosides, miliusides A-B (1 and 7), along with six known metabolites (2-6, and 8) from the leaves of Miliusa sinensis Finet and Gagnep. The structures of the purified phytochemicals were elucidated by interpreting their spectroscopic data (NMR, HRMS), as well as comparison with the previous literature. The biological evaluation of acetylcholinesterase (AChE) inhibitory effects and anti-inflammatory activity by measuring nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 mouse macrophage cells, were also conducted. Among them, compounds 5 and 7 exhibited significant AChE inhibitory activities (IC₅₀ = 53.36 ± 4.20 and 88.50 ± 8.79 µM, respectively), compared with the positive control (Galanthamine, IC₅₀ = 1.65 ± 0.15 µM). Only the MeOH extract showed suppression effects on NO production in LPS-induced RAW264.7 cells (IC₅₀ = 38.18 ± 3.25 μg/mL) comparable to that of the positive control, l-NMMA (IC₅₀ = 2.21 ± 0.56 μg/mL).

Ulmoidol, an unusual nortriterpenoid from Eucommia ulmoides Oliv. Leaves prevents neuroinflammation by targeting the PU.1 transcriptional signaling pathway

Chronic neuroinflammation is closely associated with the development of neurodegenerative diseases, including Alzheimer's disease (AD). In the current study, 13 anti-neuroinflammatory compounds were isolated from Eucommia ulmoides Oliv. leaves. Among these compounds, trans-sinapaldehyde (6), 3',4',5,7-tetrahydroxy-3-methylflavone (7), and amarusine A (13) were isolated from E. ulmoides leaves for the first time. The ursane-type C₂₉-triterpenoid, ulmoidol (ULM, 9), significantly inhibited the production of proinflammatory mediators and reduced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Moreover, ULM inhibited the cluster of differentiation 14 (CD14)/Toll-like receptor 4 (TLR4) signaling pathway and consequently limited the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Notably, electrophoretic mobility shift assay (EMSA) and molecular docking analyses indicated that ULM could prevent PU box binding-1 (PU.1) from binding to DNA, suggesting that PU.1 might be a potential ULM target. In conclusion, ULM alleviates neuroinflammatory responses in microglia, which could be partly explained by its targeting of PU.1 and the resulting suppression of the TLR4/MAPK/NF-κB signaling pathways. These results suggested that ULM may have therapeutic potential as an agent for treating neuroinflammation-related neurodegenerative diseases.

Genus Miliusa: A Review of Phytochemistry and Pharmacology

Background

Genus Miliusa (family Annonaceae), widely distributed in mainland Asia and Australia to New Guinea, has been employed in both traditional herbal uses and pharmacological medicines. Original research articles related to this genus are now available, but supportive reviews highlighting phytochemical and pharmacological aspects are now insufficient.

Objective

This account is an overview of most of the compounds isolated from this genus, along with their pharmacological evaluations.

Conclusion

A vast amount of data showed that genus Miliusa contained various classes of secondary metabolites. Herein, more than two hundred constituents were isolated, comprising alkaloids, geranylated homogentisic acids, flavonoids, lignans, neolignans, terpenoids, acetogenins, styryls, lactones, phenolics, amides, alcohols, and furfural derivatives. Novel miliusanes and bicyclic lactones have been remarkable characteristics of Miliusa plants. Essential oils from these plants were also detected, with a high amount of β-caryophyllene. Numerous in vitro biological researches on, for example, anticancer, antifungal, antimycobacterial, anti-inflammation, and cardiac activity, especially in terms of cytotoxicity, using either isolated compounds or plant extracts, implied that Miliusa phytochemical components now set out to have a key role in pharmacological development. M. smithiae ethyl acetate extract and its flavonoid ayanin (75) inhibited the growth of MCF-7 cell line comparable with positive control ellipticine. (+)-Miliusol (72) stimulated in vivo anticancer experiment against HCT116 xenograft mouse tumor following the p21-dependent induction of cellular senescence mechanism.

Phytochemical study of Juglans regia L. leaves

A methanolic extract of Juglans regia L. leaves was fractioned by various chromatographic techniques yielding a total of 40 metabolites belonging to megastigmane, tetralone, phenylpropanoid, neolignane and juglone glycosides. Ten unknown megastigmane glucoside derivatives (juglanionosides A-K, 1-10) and six unknown tetralone glucoside derivatives (juglanosides J-O, 11-16) together with 24 known compounds - among them 16 described for the first time in Juglans - were isolated. As characteristic structural feature, the previously undescribed compounds showed acylation of the sugar units with sinapic, ferulic, coumaric, benzoic or salicylic acid. Their chemical structures were elucidated on the basis of 1D and 2D NMR techniques, HRESIMS as well as CD spectroscopy. Absolute stereochemistry was revealed by mild alkaline hydrolysis and comparison of CD and polarimetric data to literature values.

Annonaceae: Breaking the Wall of Inflammation

Inventories of tropical forests have listed Annonaceae as one of the most diverse plant families. For centuries, it is employed in traditional medicines to cure various pathological conditions including snakebite, analgesic, astringent, diarrhea, dysentery, arthritis pain, rheumatism, neuralgia, and weight loss etc. Phytochemical analysis of Annonaceae family have reported the occurrence of alkaloids, flavonoids, triterpenes, diterpenes and diterpene flavone glycosides, sterols, lignans, and annonaceous acetogenin characteristically affiliated with Annonaceae sp. Numerous past studies have underlined the pleotropic pharmacological activities of the crude extracts and isolated compounds from Annonaceae species. This review is an effort to abridge the ethnobotany, morphology, phytochemistry, toxicity, and particularly focusing on the anti-inflammatory activity of the Annonaceae species.

Bicyclic lactones and racemic mixtures of dimeric styrylpyrones from the leaves of Miliusa velutina

Eight new bicyclic lactones and three new dimeric styrylpyrones from the leaves of Miliusa velutina were reported with their bioactivities.

Antimalarial Oxoprotoberberine Alkaloids from the Leaves of Miliusa cuneata

Five new oxoprotoberberine alkaloids, miliusacunines A-E (1-5), along with nine known compounds, 6-14, were isolated from an acetone extract of the leaves and twigs of Miliusa cuneata. Their structures were elucidated by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicities against the KB and Vero cell lines and for antimalarial activities against the Plasmodium falciparum strains TM4 and K1 (a sensitive and a multi-drug-resistant strain, respectively). Compound 1 showed in vitro antimalarial activity against the TM4 strain, with an IC50 value of 19.3 ± 3.4 μM, and compound 2 demonstrated significant activity against the K1 strain, with an IC50 value of 10.8 ± 4.1 μM. Both compounds showed no discernible cytotoxicity to the Vero cell line at the concentration levels evaluated.