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Eleven flavonoids including one new flavonol glycoside, quercetin-3- O -(2- α -L-rhamnopyranosyl)- β -D-glucuronopyranosyl methyl ester (1), were isolated for the first time from the fruits of Phyllanthus acidus (L.) Skeels (Phyllanthaceae). Their structures were determined by extensive spectroscopic data. The known flavonoids, quercetin-3- O - β -D-glucuronide methyl ester (3), quercetin-3- O -(2''- α -L-rhamnopyranosyl-6''- O - α -L-rhamno pyranosyl)- β -D-glucopyranoside ( 5 ), myricetin ( 9 ), and 6-methoxy-naringenin ( 11 ) were isolated for the first time from the genus Phyllanthus . Flavonoids 4 , 6 and 9 (IC 50 = 6.01, 6.32, and 7.84 μM, respectively) showed stronger α -glucosidase inhibitory activities than the positive control, acarbose (IC 50 = 306.45 μM). The fruits of P. acidus might be further developed as an anti-diabetic food supplement.

Phyllaciduloids E ( 1 ) and F ( 2 ), two new cleistanthane diterpenoids, were isolated from the leaves of Phyllanthus acidus (L.) Skeels (Phyllanthaceae). Their planar structures were established by spectroscopic analysis and comparison with literature values. The relative configurations of phyllaciduloids E and F were confirmed by DFT-NMR chemical shift calculations and subsequent CP3 probability methods. Phyllaciduloids E and F were evaluated for their cytotoxicity. However, no significant activities were detected at concentrations up to 40 μM.[Formula: see text].

Six diterpenoids including three ent-kauranes (1-2, 4) and three cleistanthanes (3, 5-6) were isolated from the roots and stems of Phyllanthus acidus (L.) Skeels. Of them, (16S)-ent-16,17,18-tri-hydroxy-19-nor-kaur-4-en-3-one (1), phyllanthone A (2), and 6-hydroxycleistanthol (3) are new compounds, while the ent-kaurane diterpenoids were reported from the titled plant for the first time. Their structures were elucidated on the basis of the extensive spectroscopic analyses. Compounds 2 and 4-6 displayed cytotoxic potential with IC 50 values ranging from 1.96 to 29.15 μM. They also showed moderate anti-inflammatory activities (IC 50  = 6.30-12.05 μM). Particularly, the new ent-kaurane 2 displayed cytotoxic potential against HL-60 (IC 50  = 2.00 μM) and MCF-7 (IC 50  = 3.55 μM) cells, and anti-inflammatory activity (IC 50  = 6.47 μM)., (Copyright © 2022. Published by Elsevier B.V.)

A novel highly oxygenated norbisabolane sesquiterpene, namely phyllanthacidoid U (1), along with nine known sesquiterpenes (2-10) was isolated from the roots and stems of Phyllanthus acidus (L.) Skeels (Phyllanthaceae), collected from Xishuangbanna, Yunnan province, China. Their structures were elucidated by means of extensive spectroscopic analysis and by comparison of their data with reported values in literatures. Instead of the C-13 ester O -glycosyl found mostly in the titled plant growing in Thailand, compound 1 possessed a rare N - β -glucosamine-2- N -acetate moiety linked directly to the carbonyl at C-13 through an amido bond. Moreover, the acyl group at C-10 in 1 was ( Z )-2-(2-hydroxyethyl)-pent-2-enedioyl group, instead of benzoic or p -hydroxybenzoic moieties found commonly in the reported norbisabolane sesquiterpenes. The known sesquiterpene 5 displayed stronger anti hepatitis B virus (HBV) activity with IC 50 values of 1.69 ± 0.22 and 2.79 ± 0.69 μM towards HBV surface antigen (HBsAg) and HBV excreted antigen (HBeAg) secretion, respectively.

The young leaves of Phyllanthus acidus (Euphorbiaceae) are commonly used as edible vegetables in Indonesia, Thailand, and India, and their water infusions as dieting aids for people trying to remain slim. However, it is regarded as a poisonous plant in Malaya, and current researches are insufficient to provide a conclusion on its toxicity and safety under large doses. In this study, we firstly found that the refined nonpolar extracts of P. acidus leaves showed significant cytotoxic effect against BEAS-2B and L02 normal cell lines with IC 50 values of 2.15 and 1.64 mg/mL, respectively. Further bioactivity-guided isolation produced four new rare dichapetalins (pacidusins A-D) from the most active fraction. Their structures including absolute configurations were elucidated by extensive spectroscopic data and X-ray diffraction analysis. All the isolated dichapetalins exhibited moderate cytotoxicity against, BEAS-2B and L02 normal cell lines with IC 50 values ranging from 12.44 to 22.55 μM, as well as five human cancer cell lines with IC 50 values ranging from 3.38 to 22.38 μM. Furthermore, the content of the main dichapetalins in the leaves were determined by analytical HPLC, which showed that the leaves contained a very high amount of the four isolated dichapetalins with a total yield of 0.488 mg/g of dry plant material. These toxic dichapetalins may lead to adverse health effects in higher doses. Our findings indicate that the dichapetalin containing leaves may not be suitable for consumption in large quantities as food, but demonstrate their potency as anti-cancer agents for new drug discovery., (Copyright © 2021. Published by Elsevier Inc.)

Phytochemical investigation on the nonpolar extracts of P. acidus leaves afforded three new cleistanthane diterpenoids, named phyllanacidins A-C (1-3), in addition to three known ones (4-6). Among them, compounds 2 and 3 represent the first examples of 17-nor cleistanthane diterpenoids. Their structures including absolute configurations were elucidated on the basis of extensive spectroscopic data and single crystal X-ray diffraction analysis. All the isolated cleistanthane diterpenoids were evaluated for their cytotoxic activities against five human cancer cell lines. Compounds 4-6 exhibited moderate cytotoxicity with IC 50 values ranging from 16.11 to 30.82 μM., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Four new cleistanthane diterpenoids, phyllaciduloids A-D (1-4), were isolated from the roots and stems of Phyllanthus acidus (L.) Skeels (Phyllanthaceae). Their structures were elucidated on the basis of extensive spectroscopic analysis. Phyllaciduloids B-D (2-4) present in their structures with ether bond between C-7 and C-16, which were rarely reported. All the isolates were evaluated for their cytotoxic activities against five human cancer cell lines., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Nineteen new highly oxygenated norbisabolane sesquiterpenoids, phyllanthacidoid acid methyl ester (1), and C-T (4-21), were isolated from Phyllanthus acidus Skeels, together with two known ones, phyllanthusols A (2) and B (3), whose sugar moiety was revised as glucosamine-N-acetate, rather than the previously assigned mannosamine-N-acetate. Compounds 2 and 3 were renamed respectively as phyllanthacidoids A (2) and B (3) to avoid confusion. All of the isolates except for 1 are glycosides, whose saccharide moieties possess a pentaoxy cyclohexane (scyllo quercitol) connecting with glucosamine-N-acetate or glucosyl moieties, which are first examples in natural products. Phyllanthacidoids N-R (15-19) with 8R configurations and/or 5,8-diketal skeleton, are unprecedented structures among norbisabolane sesquiterpenoids. Phyllanthacidoids S (20) and T (21) have the unusual tricyclo [3.1.1.1] oxygen bridge skeleton formed by a diketal system, of which the relative configurations of the aliphatic chain were assigned on the basis of heteronuclear coupling constants. The absolute configurations of compounds (1-21) were established by means of calculated electronic circular dichroism (ECD) and coupling constants. Compounds 1-5, 7-9, 10, and 14 displayed potential anti-hepatitis B virus (HBV) activities, with IC50 values of 0.8-36 μM against HBV surface antigen (HBsAg) and HBV excreted antigen (HBeAg), and the results indicated that the 5-ketal group and sugar moieties had contributions to the selectivity of HBsAg and HBeAg.

A new 6/6/5/6-fused limonoid, phyllanthoid A (1), possessing both 19/30 and 19/29 oxygen bridges was isolated from Phyllanthus cochinchinensis (Euphorbiaceae), together with a new related limonoid, phyllanthoid B (2). Their structures were determined by spectroscopic analysis and single-crystal X-ray diffraction in the case of 1. Compound 1 displayed moderate antifeedant against the generalist plant-feeding insect Spodoptera exigua and cytotoxicity against the MCF-7 cell line.

• Two rare flavonoid-sulfonic acids complexed with calcium ions were obtained. • Their structures were elucidated by spectroscopic, single-crystal X-ray diffraction analyses. • The existence of calcium was confirmed by elemental analysis. • They are the first examples of sulfonic flavonoids coordinated with calcium ions from natural products. Two rare flavonoid-sulfonic acids complexed with calcium ions, Ca (II)-6‑methoxy-8- sulfonic acid-naringenin complexes and Ca (II)-8-sulfonic acid-isoprunetin complexes, were isolated from the fruits of Phyllanthus acidus (L.) Skeels (Phyllanthaceae). Their planar structures were unambiguously established by extensive interpretation of the HRESIMS, 1D and 2D NMR data, and comparison to the literature data. The single crystal X-ray diffraction analysis revealed the location of sulfonic acid group on flavonoid C-8 position and the existence of metal atom in molecules, which was confirmed further to be calcium by elemental analysis. The two molecules represent the first examples of sulfonic flavonoids coordinated with calcium ions from the natural products. This example enriched the variety of natural product structures. All the isolates were evaluated for their antioxidant and anti-inflammatory activity. [Display omitted] [ABSTRACT FROM AUTHOR]

In an effort to identify anti-viral and cytotoxic compounds from Phyllanthus spp., 14 highly oxygenated norbisabolane sesquiterpenoids, phyllaemblicins H1–H14, were isolated from the roots of Phyllanthus emblica Linn, along with phyllaemblicins B and C and glochicoccinoside D. Their structures were determined on the basis of detailed spectroscopic analysis and chemical methods. Determination of absolute configurations of these compounds was facilitated by theoretical calculations of electronic circular dichroism (ECD) spectra using time-dependent density functional theory (TDDFT) for the aglycone components, and pre-column derivative/chiral HPLC analysis for the monosaccharides. The known glochicoccinoside D displayed potent activity against influenza A virus strain H3N2 and hand, foot and mouth virus EV71, with IC 50 values of 4.5 ± 0.6 and 2.6 ± 0.7 μg/ml, respectively. Phyllaemblicin H1 showed moderate cytotoxicity against human cancer cell lines A-549 and SMMC-7721, with IC 50 values of 4.7 ± 0.7 and 9.9 ± 1.3 μM, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Three structurally interesting new diterpenoids, phyllanflexoids A–C (1–3), together with cleistanthol (4) were isolated from the roots of Phyllanthus flexuosus. Their structures with the absolute stereochemistry were elucidated on the basis of comprehensive spectroscopic analysis, computational method, and acidic hydrolysis in the case of 3. Compounds 1–3 were phenylacetylene-bearing tricyclic diterpenes and 3 was the first example of phenylacetylene-bearing 18-nor-diterpenoid glycoside. Compounds 1, 2, and 4 exhibited weak cytotoxicity against human esophagus cancer cell ECA109 with IC50 of 42.7, 21.4, and 24.5μM, respectively. [Copyright &y& Elsevier]

Three new diterpenoids - phyllanflexoids A-C (I), (II), and (III) - are isolated from roots of Phyllanthus flexuosus. [ABSTRACT FROM AUTHOR]