Antioxidant and cytotoxic activities of Dendrobium moniliforme extracts and the detection of related compounds by GC-MS

Insights into bacterial cellulose for adsorption and sustained-release mechanism of flavors

The stabilities and sustained-release properties of citral are significant for foods. Herein, bacterial cellulose (BC) was innovatively reported for adsorption and sustained-release of citral via gas-phase adsorption technique, and the adsorption mechanism was disclosed. BC was prepared from tobacco stem waste extract (TSWE), and better adsorption capacity (124.98 mg/g) was obtained through response surface optimization. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Flourier transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) were utilized to verify the successful adsorption. Thermo-gravimetry (TG) analysis showed that the release of citral was delayed. Temperature responsiveness indicated the release of citral was controlled by internal diffusion. Density functional theory (DFT) calculations indicated the interactions between BC and citral was mainly composed of van der Waals forces and hydrogen bonds. BC-Citral also exhibited excellent antibacterial capability. This work provided a new approach for constructing controlled-release materials of citral, which offered good application prospects in food industry.

Extract from endophytic Fusarium isolates stimulates seed germination of the host and protocorm development of non-host orchids

We isolated endophytic Fusarium strains from the healthy roots, stems, and leaves of Dendrobium moschatum to investigate their plant growth-promoting activities in vitro. Subsequently, Indole acetic acid (IAA) was quantified and the IaaM gene (responsible for IAA synthesis in fungi) was amplified and sequenced. Finally, a germination assay was performed with seeds of D. moschatum and a plant growth assay with protocorms of Dendrobium longicornu to test their plant growth-promoting activities. Five Fusarium isolates (CDS11, PDL1, PDL3, PDR6, PDR7) were identified in this study. The highest amount (60µgml-1) of indole acetic acid was recorded in the PDR7 extract, whereas it was not detected in PDR6 and CDS11. The fungal extracts of isolates PDR6 and PDR7 were highly effective for seed germination by approximately 80% and 90% (respectively) of the host plant. The fungal extract of PDR7 showed a high IAA content and promoted in vitro seed germination of the host (D. moschatum) and protocorm development of the non-host (D. longicornu). In contrast, IAA content in the fungal extract of PDR6 remained undetected but was effective in both seed germination and protocorm development. Our results demonstrated the potential beneficial application of endophytic Fusarium in orchid mass propagation.

Antioxidant and L-asparaginase activities of culturable endophytic fungi from ornamental Dendrobium orchids

This study reports the antioxidant potential and L-asparaginase production of culturable fungal endophytes from Dendrobium orchids in Malaysia. Twenty-nine isolates were screened using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay to determine their free radical scavenging activities and antioxidant capacity (IC50 and AEAC). L-asparaginase production of fungal endophytes was detected by the qualitative plate assay, and the enzyme activities estimated via the Nesslerization method. All 29 endophytic isolates exhibited various degrees of radical scavenging activities (35.37%-77.23%), with Fusarium fujikuroi (D1) identified as having the highest antioxidant capacity (IC50 6.097 mg/mL) and the highest AEAC value (11.55  mg/g). For L-asparaginase production, the majority of the isolates (89.66%) showed positive results, especially among the culturable species of Fusarium, Trichoderma, and Daldinia. Most Fusarium spp. were able to produce L-asparaginase (80.77%), but the highest L-asparaginase activity was detected in Daldinia eschscholtzii (D14) with 2.128 units/mL. Results from this study highlighted the potential of endophytic fungi from medicinal orchids (Dendrobium sp.) as natural sources of bioactive compounds to be developed into novel antioxidants and anticancer drugs.

Exploring morphological variability, in vitro antioxidant potential, and HR-LCMS phytochemical profiling of Phlomis cashmeriana Royle ex Benth. across different habitats of Kashmir Himalaya

Phytochemicals are broadly acknowledged for their health-promoting effects owing to the fact of their capacity to counteract free radicals (e.g., superoxide anion radical, hydroxyl radical, hydroperoxyl radical, singlet oxygen, hypochlorite, and nitric oxide) and shield against oxidative stress induced by environmental factors. This study aimed to investigate the relationship between altitude, morphology, soil parameters, in vitro antioxidant potential and phytochemical composition of Phlomis cashmeriana collected from four different locations of Kashmir Himalaya characterized by diverse habitats and elevations. Various factors, such as extraction method, solvent polarity, and habitat conditions, can impact the quantity and efficacy of phytochemicals in plants. The aim of current study was to analyze phytochemical composition and antioxidant activity of P. cashmeriana, an important medicinal plant found in the Kashmir Himalaya region. The antioxidant activity was accessed using several assays and the plant populations were selected based on their diverse habitat features and altitudes. HR-LCMS was conducted for both below-ground and above-ground parts. Some important compounds such as, catechin, vinainsenoside, acutilobin, and kaempferol were reported for the first time from P. cashmeriana. Results showed that methanol was the most efficient solvent for extracting phytochemicals. During the current study, it was also found that the below-ground parts exhibited superior antioxidant activity compared to the above-ground parts. Notably, Site IV demonstrated the highest antioxidant potential; a positive correlation between altitude and antioxidant activity was also found. In conclusion, present research identified specific elite populations having highest antioxidant potential and are well-suited for large-scale cultivation of P. cashmeriana.

1,5,6-Trimethoxy-2,7-dihydroxyphenanthrene from Dendrobium officinale Exhibited Antitumor Activities for HeLa Cells

Natural products are irreplaceable reservoirs for cancer treatments. In this study, 12 phenanthrene compounds were extracted and isolated from Dendrobium officinale. Each chemical structure was identified using comprehensive NMR analysis. All compounds were evaluated for their cytotoxic activities against five tumor cell lines, i.e., HeLa, MCF-7, SK-N-AS, Capan-2 and Hep G2. Compound 5, 1,5,6-trimethoxy-2,7-dihydroxyphenanthrene, displayed the most significant cytotoxic effect against HeLa and Hep G2 cells, with an IC50 of 0.42 and 0.20 μM. For Hela cells, further experiments demonstrated that compound 5 could obviously inhibit cell migration, block cell cycle in the G0/G1 phase and induce apoptosis. Expression measurements for p53 indicated that knock down of p53 by siRNA could mitigate the apoptosis induced by compound 5. Therefore, the compound 5 is a potential candidate drug for HeLa cells in cervical cancer.

Uncovering the Phytochemical Profile, Antioxidant Potency, Anti-Inflammatory Effects, and Thrombolytic Activity in Dendrobium lindleyi Steud

Background. Dendrobium genus has been used in traditional medicine to treat various illnesses. The study aims at examining the phytochemical, antioxidant, anti-inflammatory, and thrombolytic properties of the leaf, stem, and root of Dendrobium lindleyi Steud, and the relationship between phytochemicals and bioactivities is determined. Results. The qualitative screening found a variety of bioactive compounds, including alkaloids, coumarins, cardiac glycosides, glycosides, flavonoids, proteins, phenols, quinines, resins, steroids, saponins, tannins, and terpenoids, in varying amounts. The quantitative screening showed the highest concentration of alkaloids in the leaves (172.15 ± 1.22 mg/g), phenols in the root (203.55 ± 0.75 mg/g), flavonoids in the root (24.35 ± 0.42 mg/g), tannins in the leaves (105.06 ± 0.55 mg/g), and proteins in the root (194.12 ± 0.65 µg/ml). The root extract showed the highest antioxidant activity (IC50 = 58.24 µg/mL), the stem extract had the most increased thrombolytic activity (IC50 = 242.74 µg/mL), and the leaf extract had the most potent anti-inflammatory activity (IC50 = 61.79 µg/mL). Statistical analysis revealed a significant positive relationship (p = 0.05) between alkaloids (r = 0.96) and tannins (r = 0.9) with antioxidant, anti-inflammatory, and thrombolytic properties. Conclusion. The bioactivities of D. lindleyi, including antioxidant (root), thrombolytic (stem), and anti-inflammatory (leaf) activities, are linked to the phytochemicals detected in the screening.

Revealing of Intracellular Antioxidants in Dendrobium nobile by High Performance Liquid Chromatography-Tandem Mass Spectrometry

The medicinal plant Dendrobium nobile is an important natural antioxidant resource. To reveal the antioxidants of D. nobile, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed for metabolic analysis. The H₂O₂-induced oxidative damage was used in human embryonic kidney 293T (H293T) cells to assess intracellular antioxidant activities. Cells incubated with flower and fruit extracts showed better cell survival, lower levels of reactive oxygen species (ROS), and higher catalase and superoxide dismutase activities than those incubated with root, stem, and leaf extracts (p < 0.01). A total of 13 compounds were newly identified as intracellular antioxidants by association analysis, including coniferin, galactinol, trehalose, beta-D-lactose, trigonelline, nicotinamide-N-oxide, shikimic acid, 5'-deoxy-5'-(methylthio)adenosine, salicylic acid, isorhamnetin-3-O-neohespeidoside, methylhesperidin, 4-hydroxybenzoic acid, and cis-aconitic acid (R² > 0.8, Log₂FC > 1, distribution > 0.1%, and p < 0.01). They showed lower molecular weight and higher polarity, compared to previously identified in vitro antioxidants in D. nobile (p < 0.01). The credibility of HPLC-MS/MS relative quantification was verified by common methods. In conclusion, some saccharides and phenols with low molecular weight and high polarity helped protect H293T cells from oxidative damage by increasing the activities of intracellular antioxidant enzymes and reducing intracellular ROS levels. The results enriched the database of safe and effective intracellular antioxidants in medicinal plants.

Phytochemical Analysis, GC-MS Profiling, and In Vitro Evaluation of Biological Applications of Different Solvent Extracts of Leonotis nepetifolia (L.) R.Br. Flower Buds

Leonotis nepetifolia (L.) R.Br. is a medicinally important herb belonging to the family Lamiaceae. The plant is typically found in tropical regions, and its leaf and root extracts are renowned for their ethno-botanical and therapeutic applications. This study was designed to determine the presence of various bioactive components, and to evaluate antibacterial, antifungal, antioxidant, and anti-proliferative activities. The preliminary phytochemical screening and gas chromatography-mass spectrometry (GC-MS) analysis of different solvent extracts revealed the presence of various bioactive compounds, of which methanol extract showed 24 compounds, petroleum ether extract revealed 26 compounds, and 24 compounds in hexane extracts. The major bioactive components including λ-sitosterol (16.20 %) in methanol extract, 1-nonadecanol (15.48 %) in petroleum extract, and eicosane (13.22 %) in hexane extract have been reported with various bio-therapeutic applications. In addition, the flower bud methanolic extract of L. nepetifolia exhibited inhibitory potential against all tested bacterial and fungal pathogens. The DPPH radical scavenging assay revealed that methanolic extract possessed the highest antioxidant activity. The scavenging activity increased in a concentration-dependent manner, as indicated by a 74 % inhibition rate at 1000 µg/ml. Furthermore, the in vitro cytotoxic effects of the methanolic extract on the HepG2 cell line were evaluated. The IC₅₀ value of methanolic extract against HepG2 cells was determined to be 83.28 µg/ml. The findings reveal that different solvent extracts of L. nepetifolia flower buds contain a significant amount of various bioactive phytochemicals with antioxidant and anticancer activities; and thus, the plant could serve as a potential source of pharmacological applications.

Development and optimization of nanoparticles loaded with erucin, a dietary isothiocyanate isolated from Eruca sativa: Antioxidant and antiproliferative activities in ehrlich-ascites carcinoma cell line

The study on Erucin (ER) has gained interest of nutraceutical and pharmaceutical industries because of its anti-cancer properties. Erucin is an isothiocyanate obtained from the seeds of Eruca sativa which possess certain drawbacks such as poor aqueous solubility and bioavailability. Therefore, the present study aimed at developing ER-cubosomes (CUB) by solvent evaporation technique followed by applying Central Composite Design to optimize ER loaded cubosomes. For this purpose, independent variables selected were Monoolein (MO) as lipid and Pluronic-84 (P-84) as a stabilizer whereas dependent variables were particle size, percentage of ER loading and percentage of its entrapment efficiency. The cubosomal nanocarriers exhibited particle size in the range of 26 nm, entrapment efficiency of 99.12 ± 0.04% and drug loading of 3.96 ± 0.0001%. Furthermore, to investigate the antioxidant potential, we checked the effect of ER and ER-CUB by DNA nicking assay, DDPH assay and Phosphomolybdate assay, and results showed significant improvement in antioxidant potential for ER-CUB than ER. Similarly, ER-CUB showed enhanced anticancer activity with a marked reduction in IC50 value than ER in MTT assay. These results suggested that ER-CUB produced notable escalation in antioxidant potential and enhanced anticancer activity than ER.

Analysis of niche shift and potential suitable distributions of Dendrobium under the impact of global climate change

Dendrobium is a valuable traditional Chinese herb that contains active ingredients such as polysaccharides and alkaloids that have anti-aging, antioxidant, and immunomodulating effects. The appropriate distribution range of Dendrobium should be predicted from the perspective of ecological niche theory in order to preserve and utilize medicinal plant resources. In this study, Dendrobium nobile, Dendrobium officinale, and Dendrobium moniliforme were selected to predict the potential suitable distributions and ecological niche shifts. A comparison of 19 environmental variables of the three Dendrobium species revealed three climatic factors that differed significantly when the species were compared two at a time. The principal component analysis was carried out in order to screen seven climatic factors for ecological niche shift analysis. All three Dendrobium species were found to have a very similar ecological niche, but with a relatively small range of variability regarding certain climatic factors. Finally, the current and future suitable areas for these three Dendrobium species in China were predicted using the MaxEnt model and ArcGIS using the two representative concentration pathways (RCP 2.6 and 8.5). Overall, the analysis of the climatic factors' comparisons, niche shift, and current and future suitable areas of these three Dendrobium species provides a basis for medicinal plant resource conservation and utilization, and our methods could be applied to the study of other similar valuable medicinal plants.

Identification of C-glycosyl flavones and O-glycosyl flavones in five Dendrobium species by high-performance liquid chromatography coupled with electrospray ionization multi-stage tandem MS

RATIONALE

Flavones are widely used in traditional Chinese medicine (TCM) and are the pharmacologically active ingredients of many medicinal plants, such as Dendrobium. With the increasing demand for medicinal Dendrobium, the identification of characteristic flavones that can serve as chemical markers for quality control is critical step for quality assurance and safety in the TCM industry.

METHODS

High-performance liquid chromatography coupled with electrospray ionization multi-stage tandem mass spectrometry (HPLC/ESI-MSⁿ ) was used to identify the chemical constituents in five types of Dendrobium: D. crystallinum, D. falconeri, D. strongylanthum, D. moniliforme, and D. gratiosissimum.

RESULTS

A total of seventy-six C-glycosyl flavones and three O-glycosyl flavones were identified, of which fifteen C-glycosyl flavones were found in D. crystallinum, twenty four were found in D. falconeri, thirty were found in D. strongylanthum, seven were found in D. moniliforme (also called "Huangtongpi", from Anhui, China), fifteen were found in D. moniliforme (also called "Zitongpi", from Yunnan, China) and seventeen were found in D. gratiosissimum. Additionally, three flavone O-glycosides were all found in D. strongylanthum.

CONCLUSIONS

The results of this study may be useful for the quality assessment and for the application of D. crystallinum, D. falconeri, D. strongylanthum, D. moniliforme, and D. gratiosissimum. This study provides comprehensive information for identification of flavones from other Chinese herbs.

A Comparison of the Flavonoid Biosynthesis Mechanisms of Dendrobium Species by Analyzing the Transcriptome and Metabolome

Dendrobium huoshanense, Dendrobium officinale, and Dendrobium moniliforme, as precious Chinese medicinal materials, have a variety of medicinal properties. Flavonoids are important medicinal components of Dendrobium, but their accumulation rules and biosynthesis mechanisms remain unclear. To explore the similarities and differences of flavonoid accumulation and biosynthesis in these three Dendrobium species, we performed flavonoid content determination, widely-targeted metabolomics and transcriptome sequencing on 1-4 years old Dendrobium species. The results showed that in different growth years, D. huoshanense stems had the highest flavonoid content in the second year of growth, while D. officinale and D. moniliforme stems had the highest flavonoid content in the third year of growth. A total of 644 differentially accumulated metabolites (DAMs) and 10,426 differentially expressed genes (DEGs) were identified by metabolomic and transcriptomic analysis. It was found that DAMs and DEGs were not only enriched in the general pathway of "flavonoid biosynthesis", but also in multiple sub-pathways such as "Flavone biosynthesis", and "Flavonol biosynthesis" and "Isoflavonoid biosynthesis". According to a combined transcriptome and metabolome analysis, the expression levels of the F3'H gene (LOC110096779) and two F3'5'H genes (LOC110101765 and LOC110103762) may be the main genes responsible for the differences in flavonoid accumulation. As a result of this study, we have not only determined the optimal harvesting period for three Dendrobium plants, but also identified the key genes involved in flavonoid biosynthesis and provided a basis for further study of the molecular mechanism of flavonoid synthesis.

Phenolic contents, anticancer, antioxidant, and antimicrobial capacities of MeOH extract from the aerial parts of Trema orientalis plant

Medicinal plants contain phytochemical components of pharmaceutical importance, and Trema orientalis MeOH extracts are believed to have potential antioxidant and cytotoxic properties. This investigation explores the phenolic, antioxidant, and anticancer property of the methanol extracts of aerial parts of T. orientalis. The total polyphenol content (TPC) and the total flavonoid contents (TFC) were determined following standard methods. In vitro antioxidant property was assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Cytotoxicity experiments were performed against eight cell lines and one fibroblast cell using the methylthiazolyldiphenyl-tetrazolium bromide assay. The antimicrobial activity assay was performed using the agar-diffusion method. Individual phenolic acids identified by GC/MS were examined in silico to estimate their drug likeness based on their structures. TPC and TFC were the highest in the leaf extract, with the strongest radical scavenging activity against ABTS (84.43%) and DPPH (79.60%) radicals. The highest cytotoxicity activity was exhibited by leaf (IC50 = 2.256 ± 0.85 μg/mL) and twig (2.704 ± 1.31 μg/mL) extracts against the HCT116 cell line, followed by bark (3.653 ± 0.05 μg/mL) and leaf (3.725 ± 0.30 μg/mL) extracts against the HT29 cell line. Clonogenicity resulted in a clear decrease of colony formation by HCT116 cells, suggesting a dose-dependent mode. In silico investigation suggested that phenolic acids detected have non-drug-like properties. Extracts showed antimicrobial inactivity.

Evaluation of chemical composition, in vitro antioxidant, and antidiabetic activities of solvent extracts of Irvingia gabonensis leaves

Irvingia gabonensis commonly referred to as wild mango or ogbono is a tropical plant with both nutritional and medicinal uses. The present study was designed to evaluate the chemical composition, in vitro antioxidant activity, and inhibitory activity of carbohydrate hydrolyzing enzymes related to diabetes by different extracts of the plant. From the results of the study, Total Phenolic Content (TPC) was highest in the aqueous and ethanol extracts (367.30 ± 00 mg/100g GAE) compared to the chloroform and n-hexane extracts whereas the Total Flavonoid Content (TFC) was highest (230.69 ± 0.18 mg/100g QE) in the ethanol extract. Analysis of the in vitro antioxidant activity showed that the ethanol extract also possessed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC₅₀: 21.42 ± 0.05 μg/ml) and hydroxyl radical scavenging activity (81.43 ± 0.11%) compared to other solvent extracts. The aqueous extract had the highest (23.91 ± 0.04 mM Fe++ equivalent) ferric antioxidant reducing power (FRAP). However, the antioxidant activity of the extracts was significantly lower than that of the reference compounds used for the study (butylated hydroxytoluene and Gallic acid). In vitro antidiabetic activity of the extracts was measured based on inhibition of α-amylase and α-glucosidase. The aqueous extract had the highest α-amylase and α-glucosidase inhibitory activity followed by the ethanol extract compared to the chloroform and n-hexane extracts. The inhibitory activity of the aqueous extract against both enzymes was higher compared to the reference compound Acarbose. Gas Chromatography-Mass Spectrometry analysis of the extracts revealed the presence of chemical constituents including fatty acids, vitamin, phytosterols, aromatic compounds, glycosides. The interaction of these compounds with α-amylase and α-glucosidase was evaluated in silico by molecular docking. Phytosterols namely, campesterol, stimasterol and γ-sitosterol had the best binding affinities to α-amylase and α-glucosidase. In conclusion, the results of this study revealed that the aqueous and ethanol extracts of Irvingia gabonensis had the highest phenolic content, antioxidant activity, and in vitro antidiabetic activity. These results offer a scientific explanation for the mode of preparation and traditional use of the plant in the treatment of diabetes.

Induction of apoptosis in A431 cells via ROS generation and p53-mediated pathway by chloroform fraction of Argemone mexicana (Pepaveraceae)

Argemone mexicana(Pepaveraceae) is an important medicinal plant commonly known as 'maxican prickly poppy' and is traditionally used to treat skin diseases. In the present study, the extract/fractions of aerial parts of A. mexicana after carrying out the organoleptic characteristics were sequentially extracted with the solvents of increasing polarities. Total fractions were examined for their radical scavenging activities in DPPH and DNA nicking assays. Among all, maximum antioxidant activity was shown by chloroform fraction (AmC) in DPPH assay with IC50 of 26.12 μg/ml, and DNA nicking assay showed 80.91% protective potential. The AmC fraction was analyzed for its antibacterial, cytotoxic potential, cell cycle analysis, mitochondrial membrane potential (MMP) and accumulation of reactive oxygen species (ROS) using A431 cell line. The AmC fraction exhibited remarkable antibacterial activity against bacterial strains in the order Klebsiella pneumoniae> Bacillussubtilis> Salmonella typhi> Staphylococcus epidermidis. The cytotoxic potential of the AmC fraction was analyzed in skin epidermoid carcinoma (A431) cells, osteosarcoma (MG-63) and cervical (HeLa) cell lines with a GI50 value of 47.04 μg/ml, 91.46 μg/ml and 102.90 μg/ml, respectively. The AmC fraction was extended further to explore its role in cell death using A431 cell line. Phase contrast and scanning electron microscopic studies on A431 cells exhibited all the characteristics indicative of apoptosis, viz., viability loss, cell shrinkage, cell rounding-off, DNA fragmentation and formation of apoptotic bodies. Flow cytometric analysis revealed enhanced ROS level, decreased MMP and arrest cell cycle at the G0/G1 phase further strengthened cell death by apoptosis. Increased expressions of apoptotic markers (p53, PUMA, cyt c, Fas and Apaf-1) were confirmed by RT-qPCR analysis. Furthermore, the AmC fraction was subjected to ultra-high-performance liquid chromatography, which revealed the presence of different polyphenols in the order: caffeic acid> epicatechin> kaempferol> chlorogenic acid> gallic acid> catechin> ellagic acid >umbeliferone> quercetin> coumaric acid. A critical analysis of results revealed that the AmC fraction induced cell death in epidermoid carcinoma cells via ROS and p53-mediated apoptotic pathway which may be ascribed to the presence of polyphenols in it.

Orchidaceae-Derived Anticancer Agents: A Review

Simple Summary

Orchids are commonly used in folk medicine for the treatment of infections and tumors but little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. According to the published data, numerous species of orchids contain potential antitumor chemicals. Still, a relatively insignificant number of species of orchids have been tested for their bioactive properties and most of those studies were on Asian taxa. Broader research, ’including American and African species, as well as the correct identification of samples, is essential for evaluating the usefulness of orchids as a plant family with huge anticancer potential.

Abstract

Species of orchids, which belong to the largest family of flowering plants, are commonly used in folk medicine for the treatment of infections and tumors. However, little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. For the assessment, previous papers on the anticancer activity of Orchidaceae published since 2015 were considered. The papers were found by exploring electronic databases. According to the available data, many species of orchids contain potential antitumor chemicals. The bioactive substances in a relatively insignificant number of orchids are identified, and most studies are on Asian taxa. Broader research on American and African species and the correct identification of samples included in the experiments are essential for evaluating the usefulness of orchids as a plant family with vast anticancer potential.

Dihydrophenanthrenes from a Sicilian Accession of Himantoglossum robertianum (Loisel.) P. Delforge Showed Antioxidant, Antimicrobial, and Antiproliferative Activities

The peculiar aspect that emerges from the study of Orchidaceae is the presence of various molecules, which are particularly interesting for pharmaceutical chemistry due to their wide range of biological resources. The aim of our study was to investigate the properties of two dihydrophenanthrenes, isolated, for the first time, from Himantoglossum robertianum (Loisel.) P. Delforge (Orchidaceae) bulbs and roots. Chemical and spectroscopic study of the bulbs and roots of Himantoglossumrobertianum (Loisel.) P. Delforge resulted in the isolation of two known dihydrophenanthrenes-loroglossol and hircinol-never isolated from this plant species. The structures were evaluated based on ¹H-NMR, ¹³C-NMR, and two-dimensional spectra, and by comparison with the literature. These two molecules have been tested for their possible antioxidant, antimicrobial, antiproliferative, and proapoptotic activities. In particular, it has been shown that these molecules cause an increase in the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) in polymorphonuclear leukocytes (PMN); show antimicrobial activity against Escherichia coli and Staphylococcus aureus, and have anti-proliferative effects on gastric cancer cell lines, inducing apoptosis effects. Therefore, these two molecules could be considered promising candidates for pharmaceutical and nutraceutical preparations.

Spectral analysis and Antibacterial activity of the bioactive principles of Sargassum tenerrimum J. Agardh collected from the Red sea, Jazan, Kingdom of Saudi Arabia

Seaweeds are a major marine resource that can be explored to develop novel pharmaceutical molecules. The present study showed the presence of unique bioactive components in the petroleum ether extract (PEE) and methanolic extract (ME) of Sargassum tenerrimum. The gas chromatography-mass spectrometry analysis suggested that the PEE of S. tenerrimum contained antibacterial biomolecules: hexadecanoic acid, methyl ester, 17-pentatriacontene, dasycarpidan-1-methanol, and acetate (ester). However, the ME of S. tenerrimum exhibited better antibacterial effect than the PEE due to the presence of the bioactive compounds 1,2-benzenedicarboxylic acid, diisooctyl ester, tetratetracontane, 1-docosene, 1,2-benzenediol, and benzoic acid. Thus, promising antibacterial molecules can be isolated from S. tenerrimum for better therapeutic use.

Traditional Uses and Pharmacologically Active Constituents of Dendrobium Plants for Dermatological Disorders: A Review

Dendrobium Sw. is one of the largest genera in the orchidaceous family and includes 900-2000 species. Among them, more than 80 Dendrobium species have been reported in China. However, there are only six Dendrobium species, namely, D. bigibbum var. superbum (syn. D. phalaenopsis), D. chrysanthum, D. fimbriatum, D. loddigesii, D. nobile, and D. officinale (syn. D. candidum), listed in the New Inventory of Existing Cosmetic Ingredients in China Launched. Artificial planting of Dendrobium species has been a great success in China. To better utilize Dendrobium resources for medicinal and cosmetic purposes, we summarize their traditional uses and pharmacologically active compounds for treating dermatological disorders in this review. "Orchidaceae", "Dendrobium", "traditional use", "ethnobotany", "dermatological disorder", and "skin disease" were used as search terms to screen the literature. Cited references were collected between 1970 and 2020 from the Web of Science, China National Knowledge Internet (CNKI), SciFinder, Google Scholar, and Chinese books. From the search, it was found that there are 22 Dendrobium species with traditional uses in dermatological disorders, and 131 compounds from Dendrobium plants have been reported to possess anti-inflammatory, antimicrobial, antioxidant, antiaging, anti-psoriasis, and tyrosinase-inhibitory activities, implying that Dendrobium plants are important resources for the discovery of active compounds and the development of new drugs and cosmetics. D. crepidatum, D. denneanum, D. loddigesii, D. nobile, and D. officinale have been extensively studied. More research on other Dendrobium species is needed. The major active compounds found in Dendrobium species are phenanthrenes, alkaloids, flavonoids, phenylpropanoids, and lignans. Several compounds, such as loddigesiinol A, (S)-5-methoxy-2,4,7,9-tetrahydroxy-9,10-dihydrophenanthrene, (S)-4-methoxy-2,5,7,9-tetrahydroxy-9,10-dihydrophenanthrene, 2,5-dihydroxy-4-methoxy-phenanthrene 2-O-β-D-glucopyranoside, (9R)-1,2,5,9-tetrahydroxy-9,10-dihydrophenanthrene 5-O-β-D-glucopyranoside, (+)-homocrepidine A, and vicenin 2, have significant anti-inflammatory activities and inhibit nitric oxide (NO) production with IC50 values less than 5 μM, and these compounds are worthy of further study.

G. sinense and P. notoginseng Extracts Improve Healthspan of Aging Flies and Provide Protection in A Huntington Disease Model

In the last decades, the strong increase in the proportion of older people worldwide, and the increased prevalence of age associated degenerative diseases, have put a stronger focus on aging biology. In spite of important progresses in our understanding of the aging process, an integrative view is still lacking and there is still need for efficient anti-aging interventions that could improve healthspan, reduce incidence of age-related disease and, eventually, increase the lifespan. Interestingly, some compounds from traditional medicine have been found to possess anti-oxidative and anti-inflammatory properties, suggesting that they could play a role as anti-aging compounds, although in depth in vivo investigations are still scarce. In this study we used one the major aging model organisms, Drosophila melanogaster, to investigate the ability of four herb extracts (HEs: Dendrobium candidum, Ophiopogon japonicum, Ganoderma sinense and Panax notoginseng) widely used in traditional Chinese medicine (TCM) to slow down aging and improve healthspan of aged animals. Combining multiple approaches (stress resistance assays, lifespan and metabolic measurements, functional heart characterizations and behavioral assays), we show that these four HEs provide in vivo protection from various insults, albeit with significant compound-specific differences. Importantly, extracts of P. notoginseng and G. sinense increase the healthspan of aging animals, as shown by increased activity during aging and improved heart function. In addition, these two compounds also provide protection in a Drosophila model of Huntington’s disease (HD), suggesting that, besides their anti-aging properties in normal individuals, they could be also efficient in the protection against age-related diseases.

A prospectus of plant growth promoting endophytic bacterium from orchid (Vanda cristata)

Background

A plant growth-promoting endophytic bacterium PVL1 isolated from the leaf of Vanda cristata has the ability to colonize with roots of plants and protect the plant. PVL1 was isolated using laboratory synthetic media. 16S rRNA gene sequencing method has been employed for identification before and after root colonization ability.

Results

Original isolated and remunerated strain from colonized roots were identified as Bacillus spp. as per EzBiocloud database. The presence of bacteria in the root section of the plantlet was confirmed through Epifluorescence microscopy of colonized roots. The in-vitro plantlet colonized by PVL1 as well as DLMB attained higher growth than the control. PVL1 capable of producing plant beneficial phytohormone under in vitro cultivation. HPLC and GC-MS analysis suggest that colonized plants contain Indole Acetic Acid (IAA). The methanol extract of Bacillus spp., contains 0.015 μg in 1 μl concentration of IAA. PVL1 has the ability to produce antimicrobial compounds such as ethyl iso-allocholate, which exhibits immune restoring property. One-way ANOVA shows that results were statistically significant at P ≤ 0.05 level.

Conclusions

Hence, it has been concluded that Bacillus spp. PVL1 can promote plant growth through secretion of IAA during root colonization and ethyl iso-allocholate to protect plants from foreign infections. Thus, this study supports to support Koch’s postulates of bacteria establishment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12896-021-00676-9.

Antioxidant Activities and Protective Effects of Dendropachol, a New Bisbibenzyl Compound from Dendrobium pachyglossum, on Hydrogen Peroxide-Induced Oxidative Stress in HaCaT Keratinocytes

Five compounds including a new bisbibenzyl named dendropachol (1) and four known compounds (2–5) comprising 4,5-dihydroxy-2,3-dimethoxy-9,10-dihydrophenanthrene (2), gigantol (3), moscatilin (4) and 4,5,4′-trihydroxy-3,3′-dimethoxybibenzyl (5) were isolated from a methanolic extract of Dendrobium pachyglossum (Orchidaceae). The chemical structures of the isolated compounds were characterized by spectroscopic methods. Dendropachol (1) was investigated for its protective effects on hydrogen peroxide (H₂O₂)-induced oxidative stress in HaCaT keratinocytes. Compound 1 showed strong free radical scavenging compared to the positive control. For the cytoprotective effect, compound 1 increased the activities of GPx and CAT and the level of GSH but reduced intracellular reactive oxygen species (ROS) generation and accumulation. In addition, compound 1 significantly diminished the expression of p53, Bax, and cytochrome C proteins, decreased the activities of caspase-3 and caspase-9, and increased Bcl-2 protein. The results suggested that compound 1 exhibited antioxidant activities and protective effects in keratinocytes against oxidative stress induced by H₂O₂.

Comparative Cytotoxic Activity of Wild Harvested Stems and In Vitro-Raised Protocorms of Dendrobium chryseum Rolfe in Human Cervical Carcinoma and Glioblastoma Cell Lines

From the medicinal orchid Dendrobium chryseum Rolfe, which is used in traditional and folk Chinese medicine, the protocorms were raised in Murashige and Skoog (MS) media in three strengths, full strength (FMS), half strength (1/2 MS), and quarter strength (1/4 MS), with or without the phytohormones 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) and coconut water (CW). The comparative cytotoxic activities of the wild and in vitro-raised protocorms were evaluated in human cervical carcinoma (HeLa) and human glioblastoma (U251) cell lines by MTT assay. In in vivo and in vitro, the methanol extracts of D. chryseum showed significant cytotoxic activities. Significant growth inhibition (%) and potent IC₅₀ values were demonstrated in HeLa cell lines (49.79% (210.5 μg/mL) for in vitro-raised Dendrobium chryseum (DCT) versus 46.97% (226.5 μg/mL) for wild Dendrobium chryseum (DCW)). Similarly, activities against U251 cell lines exhibited also significant inhibition (28.76% (612.54 μg/mL) for DCW and 17.15% (1059.92 μg/mL) for DCT). The cytotoxic activities of both, wild and tissue-cultured samples, were superior in HeLa cells. In U251 cells, the wild sample was more active than the tissue-cultured one with a moderate cytotoxic effect. Hence, protocorm culture may therefore be a promising future tool for producing pharmacologically bioactive compounds in medicinal orchids. Such sustainable technology approach will minimize the pressure on the natural population of threatened but commercially important medicinal orchids.

Six phenanthrenes from the roots of Cymbidium faberi Rolfe. and their biological activities

A new phenanthrene compound, 7-(4-hydroxybenzyl)-8-methoxy-9,10- dihydrophenanthrene-2,5-diol (HMD), along with five known compounds (Coelonin, DD, Shancidin, HDP and MDD) were isolated from the roots of Cymbidium faberi Rolfe. (CFR). Their structures were identified using various spectroscopic methods. These compounds were reported for the first time in the genus. All isolated compounds were tested by radical-scavenging ability against 1,1-diphenyl-2-picryl-hydrazyl (DPPH), cytotoxic activity against three human cancer cell lines and inflammatory activity. Among them, Shancidin exhibited the stronger DPPH-scavenging activity (IC₅₀=6.67 ± 0.84 μΜ) and cytotoxic activity against three tumour cell lines. Except for HDP, all compounds dose-dependently suppressed production of NO, TNF-α, IL-6 in LPS induced mouse primary peritoneal macrophage and showed anti-inflammatory activity. Moreover, 18 compounds were identified by UHPLC-LTQ-Orbitrap-MS combined with MS database, which provides a basis for further research.

Cytotoxic Phenanthrene, Dihydrophenanthrene, and Dihydrostilbene Derivatives and Other Aromatic Compounds from Combretum laxum

The chemical investigation of the roots and stems of Combretum laxum yielded a new dihydrostilbene derivative, 4'-hydroxy-3,3',4-trimethoxy-5-(3,4,5-trimethoxyphenoxy)-bibenzyl (1), two phenanthrenes (2-3), and three dihydrophenanthrenes (4-6), along with one lignan, three triterpenoids, one aurone, one flavone, one naphthoquinone, and two benzoic acid derivatives. Their structures were determined by 1D and 2D nuclear magnetic resonance (NMR) spectroscopic techniques and/or mass spectrometry data. The occurrence of dihydrostilbenoid, phenanthrene and dihydrophenanthrene derivatives is unprecedented in a Combretum species native to the American continent. 2,7-Dihydroxy-4,6-dimethoxyphenanthrene, 2,6-dihydroxy-4,7-dimethoxy-9,10-dihydrophenanthrene and 5-O-methyl apigenin are novel findings in the Combretaceae, as is the isolation of compounds belonging to the chemical classes of aurones and naphthoquinones, while (+)-syringaresinol is reported for the first time in the genus Combretum. Compounds 1-6 were also evaluated for their in vitro cytotoxicity against five human cancer cell lines, and radical-scavenging ability against 1,1-diphenyl-2-picryl-hydrazyl (DPPH). 6-Methoxycoelonin (4) was the most cytotoxic against melanoma cells (IC₅₀ 2.59 ± 0.11 µM), with a high selectivity index compared with its toxicity against nontumor mammalian cells (SI 25.1). Callosin (6), despite exhibiting the strongest DPPH-scavenging activity (IC₅₀ 17.7 ± 0.3 µM), proved marginally inhibitory to the five cancer cell lines tested, indicating that, at least for these cells, antioxidant potential is unrelated to antiproliferative activity.

Cytotoxic effect of selected wild orchids on two different human cancer cell lines

Majority of the orchid species are used in the traditional medicines for the treatment of several diseases. They are the sources of polysaccharides, phenanthrenes, bibenzyl derivatives, revesteral, stilbenoids and polyphenol compounds. This study explored the cytotoxic activity of seven wild orchid species and identification of medicinally active compounds. The extracts of orchid species were screened for cytotoxic effect on the human cervical cancer cells (HeLa) and human glioblastoma cells (U251) using an MTT assay. The medicinally active compounds of high cytotoxic extracts were identified by GC-MS resulting in many stilbenoids and phenolic derivatives. The extract of Dendrobium transparens (DTs) and Vanda cristata (VCw) showed high cytotoxic effect towards the HeLa and U251 cell lines (IC50 of DTs: 382.14 μg/ml and 75.84 μg/ml respectively and IC50 of VCw: 317.23 μg/ml and 163.66 μg/ml respectively). This study concludes that they could be used as cancer therapeutics.

Interactions Between Gut Microbiota, Host, and Herbal Medicines: A Review of New Insights Into the Pathogenesis and Treatment of Type 2 Diabetes

Herbal medicines (HMs) are a major subset of complementary and alternative medicine. They have been employed for the efficient clinical management of type 2 diabetes mellitus (T2DM) for centuries. However, the related underlying mechanisms still remain to be elucidated. It has been found out that microbiota is implicated in the pathogenesis and treatment of T2DM. An interplay between gut microbiota and host occurs mainly at the gastrointestinal mucosal barrier. The host movements influence the composition and abundance of gut microbiota, whereas gut microbiota in turn modulate the metabolic and immunological activities of the host. Intestinal dysbiosis, endotoxin-induced metabolic inflammation, immune response disorder, bacterial components and metabolites, and decreased production of short-chain fatty acids are considered significant pathogenic mechanisms underlying T2DM. The interaction between gut microbiota and HMs during T2DM treatment has been investigated in human, animal, and in vitro studies. HMs regulate the composition of beneficial and harmful bacteria and decrease the inflammation caused by gut microbiota. Furthermore, the metabolism of gut microbiota modulates HM biotransformation. In this review, we have summarized such research findings, with the aim to improve our understanding of the pathogenesis and potential therapeutic mechanisms of HMs in T2DM and to provide new insights into specific targeted HM-based therapies and drug discovery.

Assessment of Antioxidant and Cytotoxic Activities of Extracts of Dendrobium crepidatum

Dendrobium crepidatum is an epiphytic orchid found in south Asia including Nepal and China. This orchid species is widely used in traditional Chinese medicine (TCM) for the treatment of cancer, diabetes, cataracts, and fever. The objectives of the present research were to assess the antioxidant and cytotoxic properties of its stem’s extracts with the identification of bioactive secondary metabolites. The antioxidant and cytotoxic activities were evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, respectively, and compounds were identified using GC–MS (gas chromatography and mass spectrometry). Ethanol and acetone extracts scavenged 94.69 ± 0.10% and 93.41 ± 0.86% of DPPH free radicals, respectively. They showed 50% inhibition of DPPH free radicals (IC₅₀) at concentrations of 73.90 µg/mL and 99.44 µg/mL, which were found to be statistically similar to that of ascorbic acid (control). Chloroform extract inhibited the growth of 81.49 ± 0.43% of HeLa (human cervical carcinoma) cells and hexane extract inhibited the growth of 76.45 ± 4.26% of U251 (human glioblastoma) cells at 800 µg/mL concentration. These extracts showed 50% inhibition of cell growth (IC₅₀) toward both the HeLa and U251 cell lines at their high concentrations, which were found statistically significantly different from that of cisplatin drug (control). The above extracts showed antioxidant and cytotoxic properties, potentially due to the presence of tetracosane, triacontane, stigmasterol, and some phenol derivatives (2-methoxy-4-vinylphenol, 2-methoxy-5-(1-propenyl)-phenol, p-mesyloxyphenol, and 2,6-dimethoxy-4-(2-propenyl)-phenol). This study explores the potential of this orchid in alternative medicine toward the development of drugs from its medicinally active compounds.