New Phenolic Glycosides from Coelogyne fuscescens Lindl. var. brunnea and Their Cytotoxicity against Human Breast Cancer Cells.

The phytochemical investigation of the whole plants of Coelogyne fuscescens Lindl. var. brunnea led to the discovery of three new phenolic glycosides, i.e., coelofusides A-C (1-3) and 12 known compounds (4-15). For the first time, we reported the nuclear magnetic resonance (NMR) data of 4-O-(6'-O-glucosyl-4″-hydroxybenzoyl)-4-hydroxybenzyl alcohol (4) in this study. The identification of the structures of newly discovered compounds was done through the analysis of their spectroscopic data [NMR, mass spectrometry, ultraviolet, Fourier transform infrared, optical rotation, and circular dichroism (CD)]. In comparison to anticancer drugs (i.e., etoposide and carboplatin), we evaluated anticancer potential of the isolated compounds on two different breast cancer cell lines, namely, T47D and MDA-MB-231. Human fibroblast HaCaT cells were used as the control cells. After a 48 h incubation, flavidin (8), coelonin (10), 3,4-dihydroxybenzaldehyde (11), and oxoflavidin (12) showed significant cytotoxic effects against breast cancer cells. Among them, oxoflavidin (12) exhibited the most potent cytotoxicity on MDA-MB-231 with an IC50 value of 26.26 ± 4.33 µM. In the nuclear staining assay, oxoflavidin induced apoptosis after 48 h in both T47D and MDA-MB-231 cells in a dose-dependent manner. Furthermore, oxoflavidin upregulated the expression of apoptotic genes, such as p53, Bax, poly(ADP-ribose) polymerase, caspase-3, and caspase-9 genes while significantly decreasing antiapoptotic protein (Bcl-2) expression levels.

Diverse modulatory effects of bibenzyls from Dendrobium species on human immune cell responses under inflammatory conditions.

Dendrobium plants are widely used in traditional Chinese medicine. Their secondary metabolites such as bibenzyls and phenanthrenes show various pharmacological benefits such as immunomodulation and inhibitory effects on cancer cell growth. However, our previous study also showed that some of these promising compounds (i.e., gigantol and cypripedin) also induced the expression of inflammatory cytokines including TNF in human monocytes, and thus raising concerns about the use of these compounds in clinical application. Furthermore, the effects of these compounds on other immune cell populations, apart from monocytes, remain to be investigated. In this study, we evaluated immunomodulatory effects of seven known bibenzyl compounds purified from Dendrobium species in human peripheral blood mononuclear cells (PBMCs) that were stimulated with lipopolysaccharide (LPS). Firstly, using flow cytometry, moscatilin (3) and crepidatin (4) showed the most promising dose-dependent immunomodulatory effects among all seven bibenzyls, determined by significant reduction of TNF expression in LPS-stimulated CD14+ monocytes. Only crepidatin at the concentration of 20 µM showed a significant cytotoxicity, i.e., an increased cell death in late apoptotic state. In addition, deep immune profiling using high-dimensional single-cell mass cytometry (CyTOF) revealed broad effects of Dendrobium compounds on diverse immune cell types. Our findings suggest that to precisely evaluate therapeutic as well as adverse effects of active natural compounds, a multi-parameter immune profiling targeting diverse immune cell population is required.

Potential role of a novel biphenanthrene derivative isolated from Aerides falcata in central nervous system diseases.

Central nervous system (CNS) diseases are a significant health burden globally, with the development of novel drugs lagging behind clinical needs. Orchidaceae plants have been traditionally used to treat CNS diseases, leading to the identification of therapeutic leads against CNS diseases from the Aerides falcata orchid plant in the present study. The study isolated and characterized ten compounds, including a previously undescribed biphenanthrene derivative, Aerifalcatin (1), for the first time from the A. falcata extract. The novel compound 1 and known compounds, such as 2,7-dihydroxy-3,4,6-trimethoxyphenanthrene (5), agrostonin (7), and syringaresinol (9), showed potential activity in CNS-associated disease models. Notably, compounds 1, 5, 7, and 9 demonstrated the ability to alleviate LPS-induced NO release in BV-2 microglial cells, with IC50 values of 0.9, 2.5, 2.6, and 1.4 µM, respectively. These compounds also significantly inhibited the release of pro-inflammatory cytokines, IL-6 and TNF-α, reflecting their potential anti-neuroinflammatory effects. Additionally, compounds 1, 7, and 9 were found to reduce cell growth and migration of glioblastoma and neuroblastoma cells, indicating their potential use as anticancer agents in the CNS. In summary, the bioactive agents isolated from the A. falcata extract offer plausible therapeutic options for CNS diseases.

Phytochemicals from Vanda bensonii and Their Bioactivities to Inhibit Growth and Metastasis of Non-Small Cell Lung Cancer Cells

The most prevalent lung cancer is non-small cell lung cancer (NSCLC). This lung cancer type often develops other organ-specific metastases that are critical burdens in the treatment process. Orchid species in the genus Vanda have shown their potential in folkloric medication of diverse diseases but not all its species have been investigated, and little is known about their anticancer activities against NSCLC. Here, we firstly profiled the specialized metabolites of Vanda bensonii and examined their capability to inhibit growth and metastasis of NSCLC using NCI-H460 cells as a study model. Four phytochemicals, including phloretic acid methyl ester (1), cymbinodin-A (2), ephemeranthoquinone B (3), and protocatechuic acid (4), were isolated from the whole plant methanolic extract of V. bensonii. The most distinguished cytotoxic effect on NCI-H460 cells was observed in the treatments with crude methanolic extract and compound 2 with the half maximal inhibitory concentrations of 40.39 µg mL−1 and 50.82 µM, respectively. At non-cytotoxic doses (10 µg mL−1 or 10 µM), only compound 1 could significantly limit NCI-H460 cell proliferation when treated for 48 h, while others excluding compound 4 showed significant reduction in cell proliferation after treating for 72 h. Compound 1 also significantly decreased the migration rate of NCI-H460 cells examined through a wound-healing assay. Additionally, the crude extract and compound 1 strongly affected survival and growth of NCI-H460 cells under anchorage-independent conditions. Our findings proved that natural products from V. bensonii could be promising candidates for the future pharmacotherapy of NSCLC.

Three New Dihydrophenanthrene Derivatives from Cymbidium ensifolium and Their Cytotoxicity against Cancer Cells.

From the aerial parts of Cymbidium ensifolium, three new dihydrophenanthrene derivatives, namely, cymensifins A, B, and C (1−3) were isolated, together with two known compounds, cypripedin (4) and gigantol (5). Their structures were elucidated by analysis of their spectroscopic data. The anticancer potential against various types of human cancer cells, including lung, breast, and colon cancers as well as toxicity to normal dermal papilla cells were assessed via cell viability and nuclear staining assays. Despite lower cytotoxicity in lung cancer H460 cells, the higher % apoptosis and lower % cell viability were presented in breast cancer MCF7 and colon cancer CaCo2 cells treated with 50 µM cymensifin A (1) for 24 h compared with the treatment of 50 µM cisplatin, an available chemotherapeutic drug. Intriguingly, the half-maximum inhibitory concentration (IC50) of cymensifin A in dermal papilla cells at >200 µM suggested its selective anticancer activity. The obtained information supports the further development of a dihydrophenanthrene derivative from C. ensifolium as an effective chemotherapy with a high safety profile for the treatment of various cancers.

Amycolatopsis dendrobii sp. nov., an endophytic actinomycete isolated from Dendrobium heterocarpum Lindl.

Three novel actinomycete strains, designated as DR6-1T, DR6-2 and DR6-4, isolated from the roots of Dendrobium heterocarpum Lindl in Thailand were studied using a polyphasic taxonomic approach. The strains grew at 20-37 °C, at pH 5-10 and with 5 % (w/v) NaCl. They contained meso-diaminopimelic acid in the cell-wall peptidoglycan and MK-9(H4) was a major menaquinone. Arabinose and galactose were the major sugars in the cell wall. The predominant cellular fatty acids were iso-C16 : 0 and iso-C15 : 0. The detected polar lipids were diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylglycerol. Strains DR6-1T, DR6-2 and DR6-4 shared 99.9-100 % 16S rRNA gene sequence similarity and were closely related to Amycolatopsis echigonensis JCM 21831T (98.7-98.8%). The approximate genome size of strain DR6-1T was 9.6 Mb with a G+C content of 69.6 mol%. The ANIb and dDDH values between genomic sequences of strain DR6-1T and Amycolatopsis echigonensis JCM21831T, Amycolatopsis rubida JCM 10871T and Amycolatopsis nivea KCTC 39515T were 90.55, 92.25, 92.60%, and 47.20, 52.10 and 52.50%, respectively. Based on the phenotypic, chemotaxonomic and genotypic characteristics, it has been concluded that strains DR6-1T, DR6-2 and DR6-4 represent a novel species of the genus Amycolatopsis for which the name Amycolatopsis dendrobii sp. nov. is proposed. The type strain is DR6-1T (=JCM 33742T=KCTC 49546T=TISTR 2840T).

Oxyresveratrol: Sources, Productions, Biological Activities, Pharmacokinetics, and Delivery Systems.

Oxyresveratrol has recently attracted much research attention due to its simple chemical structure and diverse therapeutic potentials. Previous reviews describe the chemistry and biological activities of this phytoalexin, but additional coverage and greater accessibility are still needed. The current review provides a more comprehensive summary, covering research from 1955 to the present year. Oxyresveratrol occurs in both gymnosperms and angiosperms. However, it has never been reported in plants in the subclass Sympetalae, and this point might be of both chemotaxonomic and biosynthetic importance. Oxyresveratrol can be easily obtained from plant materials by conventional methods, and several systems for both qualitative and quantitative analysis of oxyresveratrol contents in plant materials and plant products are available. Oxyresveratrol possesses diverse biological and pharmacological activities such as the inhibition of tyrosinase and melanogenesis, antioxidant and anti-inflammatory activities, and protective effects against neurological disorders and digestive ailments. However, the unfavorable pharmacokinetic properties of oxyresveratrol, including low water solubility and poor oral availability and stability, have posed challenges to its development as a useful therapeutic agent. Recently, several delivery systems have emerged, with promising outcomes that may improve chances for the clinical study of oxyresveratrol.

Improvement of stilbene production by mulberry Morus alba root culture via precursor feeding and co-elicitation.

Large amounts of Morus alba L. (MA) roots are needed as the source of active stilbenes in the industrial production of traditional medicines and cosmeceuticals. A recent investigation demonstrated resveratrol and its derivatives to be promising anti-COVID-19 agents. However, conventional cultivation of MA does not meet the demand for its stilbenes, and root quality usually varies between crops. This study established the in vitro non-GMO root culture of MA and optimized the root density, precursor feeding, and elicitors for stilbene productivity. A root culture with optimal inoculum density (3 g/flask of 30 mL medium) accumulated mulberroside A, oxyresveratrol, and resveratrol at 18.7 ± 1.00 mg/g, 136 ± 5.05 µg/g, and 41.6 ± 5.84 µg/g dry weight (DW), respectively. The feeding of L-tyrosine shortened the time required to reach the stilbene productive stage. Root cultures co-treated with 200 µM methyl jasmonate and 2 mg/mL yeast extract accumulated the highest contents of mulberroside A (30.3 ± 2.68 mg/g DW), oxyresveratrol (68.6 ± 3.53 µg/g DW), and resveratrol (10.2 ± 0.53 µg/g DW). In summary, root culture is a promising and sustainable source of stilbenes for the development of health products and agents for further investigation as potential anti-COVID-19 agents.

Immune modulatory effect of a novel 4,5-dihydroxy-3,3´,4´-trimethoxybibenzyl from Dendrobium lindleyi.

Dendrobium bibenzyls and phenanthrenes such as chrysotoxine, cypripedin, gigantol and moscatilin have been reported to show promising inhibitory effects on lung cancer growth and metastasis in ex vivo human cell line models, suggesting their potential for clinical application in patients with lung cancer. However, it remains to be determined whether these therapeutic effects can be also seen in primary human cells and/or in vivo. In this study, we comparatively investigated the immune modulatory effects of bibenzyls and phenanthrenes, including a novel Dendrobium bibenzyl derivative, in primary human monocytes. All compounds were isolated and purified from a Thai orchid Dendrobium lindleyi Steud, a new source of therapeutic compounds with promising potential of tissue culture production. We detected increased frequencies of TNF- and IL-6-expressing monocytes after treatment with gigantol and cypripedin, whereas chrysotoxine and moscatilin did not alter the expression of these cytokines in monocytes. Interestingly, the new 4,5-dihydroxy-3,3',4'-trimethoxybibenzyl derivative showed dose-dependent immune modulatory effects in lipopolysaccharide (LPS)-treated CD14lo and CD14hi monocytes. Together, our findings show immune modulatory effects of the new bibenzyl derivative from Dendrobium lindleyi on different monocyte sub-populations. However, therapeutic consequences of these different monocyte populations on human diseases including cancer remain to be investigated.

A Self-Microemulsifying Formulation of Oxyresveratrol Prevents Amyloid Beta Protein-Induced Neurodegeneration in Mice.

The polyphenol compound, oxyresveratrol (OXY) possesses potent antioxidant and neuroprotective properties of potential utility in the treatment of Alzheimer's disease. However, the low oral bioavailability limits its neuroprotective effect and clinical application. The neuroprotective effect of orally administered OXY-loaded self-microemulsifying drug delivery system (OXY-SMEDDS) was compared with free OXY in vivo. Mice were orally administered either free OXY or OXY-SMEDDS once daily at a dose of 90, 180, or 360 mg/kg for 14 d. Mice received a single intracerebroventricular injection of the neurotoxic amyloid ß (Aß)25 - 35 peptide at day 8 during oral treatment. The OXY-SMEDDS formulation resulted in four-times reduction of the free OXY dose required for prevention of neurotoxicity effects due to Aß25 - 35 peptide as demonstrated by a significant decline in behavior impairments, lipid oxidation levels, and neuronal cell loss in all hippocampal subfields (p < 0.0001). These results indicate the potential of OXY-SMEDDS by oral delivery to improve the efficacy of this compound in the treatment of Alzheimer's disease.

α-Glucosidase and pancreatic lipase inhibitory activities and glucose uptake stimulatory effect of phenolic compounds from Dendrobium formosum

ABSTRACT A methanol extract from the whole plant of Dendrobium formosum Roxb. ex Lindl., Orchidaceae, showed inhibitory potential against α-glucosidase and pancreatic lipase enzymes. Chromatographic separation of the extract resulted in the isolation of twelve phenolic compounds. The structures of these compounds were determined through analysis of NMR and HR-ESI-MS data. All of the isolates were evaluated for their α-glucosidase and pancreatic lipase inhibitory activities, as well as glucose uptake stimulatory effect. Among the isolates, 5-methoxy-7-hydroxy-9,10-dihydro-1,4-phenanthrenequinone (12) showed the highest α-glucosidase and pancreatic lipase inhibitory effects with an IC50 values of 126.88 ± 0.66 µM and 69.45 ± 10.14 µM, respectively. An enzyme kinetics study was conducted by the Lineweaver-Burk plot method. The kinetics studies revealed that compound 12 was a non-competitive inhibitor of α-glucosidase and pancreatic lipase enzymes. Moreover, lusianthridin at 1 and 10 µg/ml and moscatilin at 100 µg/ml showed glucose uptake stimulatory effect without toxicity on L6 myotubes. This study is the first report on the phytochemical constituents and anti-diabetic and anti-obesity activities of D. formosum.

A New Bibenzyl-phenanthrene Derivative from Dendrobium signatum and its Cytotoxic Activity.

From the whole plant of Dendrobium signatum, a new bibenzyl-dihydrophenanthrene derivative, named dendrosignatol was isolated, together with the known compounds 3,4-dihydroxy-3,4'-dimethoxybibenzyl, dendrocandin B, dendrocandin I and dendrofalconerol A. The structure of the new compound was elucidated through analysis of its spectroscopic and mass spectrometric data. All of the isolates showed appreciable cytotoxic activity against three human cancer cell lines, including MDA-23 1, HepG2 and HT-29 cells.

Antioxidant, DNA damage protective, neuroprotective, and α-glucosidase inhibitory activities of a flavonoid glycoside from leaves of Garcinia gracilis

Abstract The leaves of Garcinia gracilis Pierre, Clusiaceae, have been used as flavouring materials in food, with no previous reports of their biological activities and chemical constituents. In this study, the methanolic extract of G. gracilis afforded three compounds namely apigenin-8-C-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (1), 5-hydroxymethyl-2-furaldehyde, and vanillic acid. All of the isolates were initially evaluated for superoxide anion radical scavenging activity and α-glucosidase inhibitory effects. Compound 1, which was the major component, showed the most potent activities among these three isolates. Further biological evaluations revealed that compound 1 could prevent the pBR322 plasmid DNA damage induced by the photochemical reaction of riboflavin and protect P19-derived neurons from the oxidative stress condition induced by serum deprivation. It was concluded that the potent biological activities of G. gracilis could be attributed to the synergistic effect of compound 1 with other constituents found in the plant.

Oxyresveratrol: Structural Modification and Evaluation of Biological Activities.

Oxyresveratrol (2,4,3',5'-tetrahydroxystilbene, 1), a phytoalexin present in large amounts in the heartwood of Artocarpus lacucha Buch.-Ham., has been reported to possess a wide variety of biological activities. As part of our continuing studies on the structural modification of oxyresveratrol, a library of twenty-six compounds was prepared via O-alkylation, aromatic halogenation, and electrophilic aromatic substitution. The two aromatic rings of the stilbene system of 1 can be chemically modulated by exploiting different protecting groups. Such a strategy allows for selective and exclusive modifications on either ring A or ring B. All compounds were evaluated in vitro for a panel of biological activities, including free radical scavenging activity, DNA protective properties, antiherpetic activity, inhibition of α-glucosidase and neuraminidase, and cytotoxicity against some cancer cell lines. Several derivatives were comparably active or even more potent than the parent oxyresveratrol and/or the appropriate positive controls. The partially etherified analogs 5'-hydroxy-2,3',4-trimethoxystilbene and 3',5'-dihydroxy-2,4-dimethoxystilbene demonstrated promising anti-herpetic and DNA protective activities, offering new leads for neuropreventive agent research, whereas 5'-hydroxy-2,3',4,-triisopropoxystilbene displayed anti-α-glucosidase effects, providing a new lead molecule for anti-diabetic drug development. 3',5'-Diacetoxy-2,4-diisopropoxystilbene showed potent and selective cytotoxicity against HeLa cancer cells, but the compound still needs further in vivo investigation to verify its anticancer potential.

Cytotoxic and Antimigratory Activities of Phenolic Compounds from Dendrobium brymerianum.

Chromatographic separation of a methanol extract prepared from the whole plant of Dendrobium brymerianum led to the isolation of eight phenolic compounds. Among the isolated compounds (1-8), moscatilin (1), gigantol (3), lusianthridin (4), and dendroflorin (6) showed appreciable cytotoxicity against human lung cancer cell lines with IC50 values of 196.7, 23.4, 65.0, and 125.8 µg/mL, respectively, and exhibited antimigratory property at nontoxic concentrations. This study is the first report on the biological activities of this plant.

Cytotoxic and anti-metastatic activities of phenolic compounds from Dendrobium ellipsophyllum.

BACKGROUND/AIM: Phenolic compounds isolated from Dendrobium ellipsophyllum Tang & Wang (Orchidaceae) have been shown to possess potential pharmacological activity; however, their anticancer as well as anti-metastasis activities are largely unknown. The aim of the present study was to isolate active compounds from D. ellipsophyllum and to explore the possible effects of phenolic compounds isolated from the plant for cytotoxic as well as anti-metastatic properties. MATERIALS AND METHODS: The compounds were isolated by using chromatographic techniques including silica gel and Sephadex LH20. Each of the isolates was evaluated for their cytotoxicity on H292 human lung cancer cell lines by 2,3-Bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. The cytotoxic compounds were further evaluated for apoptosis-inducing and anoikis-sensitizing effects. RESULTS: Ten phenolic compounds were isolated, 5,7-dihydroxy-chromen-4-one (1:); 4,5-dihydroxy-2,3-dimethoxy-9,10-dihydrophenanthrene (2:); moscatilin (3:), 4,4'-dihydroxy-3,5-dimethoxybibenzyl (4:); 4,5,4'-trihydroxy-3,3'-dimethoxybibenzyl (5:); (2S)-homoeriodictyol (6:); (2S)-eriodictyol (7:); chrysoeriol (8:); phloretic acid (9:); and luteolin (10:). Compounds 4:, 5:, 8: and 10: exhibited appreciable cytotoxic activity with 50% inhibitory concentration values less than 250 µM. These compounds also showed potential apoptosis induction and anoikis-sensitizing effect at non-toxic concentrations. CONCLUSION: Compounds 4:, 5:, 8: and 10: are responsible for cytotoxic and anti-metastatic activities of D. ellipsophyllum.

Anti-metastatic activities of bibenzyls from Dendrobium pulchellum.

Our investigation of the stem of Dendrobium pulchellum resulted in the isolation of four known bibenzyls, chrysotobibenzyl (1), chrysotoxine (2), crepidatin (3) and moscatilin (4). The present study reveals for the first time the ability of these four compounds to facilitate anoikis and inhibit the growth of lung cancer cells in anchorage-independent condition. The preliminary data obtained disclose the inhibitory effect on cancer cell metastasis of the isolated compounds, and provide an important new approach for cancer drug development.

Neolignans from leaves of Miliusa mollis.

From the leaves of Miliusa mollis Pierre (Annonaceae), five new dihydrobenzofuran neolignans, namely miliumollin, 7-methoxymiliumollin, 3'-methoxymiliumollin, 4'-O-methylmiliumollin and miliumollinone, and a new 8-O-4' neolignan named miliusamollin were isolated, and their structures were elucidated through analysis of spectroscopic data. Miliumollin, 3'-methoxymiliumollin, miliumollinone and decurrenal exhibited weak cytotoxicity against KB, MCF7 and NCI-H187 cells. Miliumollinone possessed weak inhibitory effects against herpes simplex virus types 1 and 2. None of the isolates displayed inhibitory activity against avian influenza H5N1 neuraminidase.

Flavonoid and stilbenoid production in callus cultures of Artocarpus lakoocha.

Callus cultures of Artocarpus lakoocha Roxb., established from seedling explants and maintained on woody plant medium containing 1mg/l 2,4-dichlorophenoxyacetic acid and 1mg/l benzyladenine, were studied for their chemical constituents and biosynthetic potential of secondary metabolites. Four prenylflavones and prenylated stilbenes, along with nine known polyphenolic compounds, were isolated and elucidated for their structures through extensive analysis of their NMR and MS data. Among the 13 isolates, it appeared that seven of them are prenylated derivatives of 5,7,2',4'-tetrahydroxyflavones, and four are prenylated derivatives of 2,4,3',5'-tetrahydroxystilbene (oxyresveratrol), suggesting that the biosynthetic pathways of these two polyphenolic groups and their prenylating enzymes are highly expressed in A. lakoocha callus cultures. A study on the growth-product relationship of the callus cultures showed that the secondary metabolites were all formed simultaneously during the rapid growth phase of the culture cycle, with various prenylflavones, and a prenylated stilbene as major constituents. In assays for DPPH free radical scavenging activity and tyrosinase inhibitory potential, the stilbenoids appeared to possess moderate effects, whereas the flavonoids showed only weak activity.

New phenolic compounds from Dendrobium capillipes and Dendrobium secundum.

Phytochemical investigation of the stem of Dendrobium capillipes resulted in the isolation of a new flavonol glycoside namely quercetin-3-O-α-L-rhamnopyranosyl-(1 → 2)-ß-d-xylopyranoside, along with seven known phenolic compounds which included two flavonol glycosides and five bibenzyls. From the stem of Dendrobium secundum, a new compound named 5-hydroxy-3,4,3',4',5'-pentamethoxybibenzyl was characterized, together with two known bibenzyls and three glycosidic flavonoids. Some of the isolated bibenzyls showed cytotoxicity against KB, NCI-H187, and MCF-7 cancer cells, whereas all of the glycosidic flavonoids were devoid of activity.