Thevetia thevetioides Cardenolide and Related Cardiac Glycoside Profile in Mature and Immature Seeds by High-Resolution Thin-Layer Chromatography (HPTLC) and Quadrupole Time of Flight-Tandem Mass Spectrometry (Q-TOF MS/MS) Reveals Insights of the Cardenolide Biosynthetic Pathway.

Thevetia thevetioides is a species within the Apocynaceae family known for containing cardenolide-glycosides, commonly referred to as cardiac glycosides, which are characteristic of this genus. The seeds of the Thevetia species are frequently used as a model source for studying cardiac steroids, as these glycosides can be more readily extracted from the oil-rich seeds than from the plant's green tissues. In this work, the cardenolide profile of ripe and immature seeds was determined and compared to establish the main differences. Ripe seeds contain six related cardenolides and triosides, with thevetin B being the predominant component. In contrast, immature seeds exhibit a total of thirteen cardiac glycosides, including monoglycosides such as neriifolin and peruvosides A, B, and C, as well as diglycosides like thevebiosides A, B, and C. Some of these compounds have previously been identified as degradation products of more complex cardiac glycosides; however, their presence in immature seeds, as described in this study, suggests that they may serve as biosynthetic precursors to the triosides observed in mature seeds. The glycoside patterns observed via HPTLC are associated with specific chemical structures characteristic of this genus, typically featuring thevetose or acetyl-thevetose at the first position, followed by glucose or gentibiose in di- or trisaccharides, independent of the trioside aglycones identified: digitoxigenin, cannogenin, or yccotligenin. Ripe seeds predominantly contain triosides, including thevetin B, C, and A, the latter of which has not been previously reported.

Caralluma pauciflorabased Ag-NPs activate ROS - induced apoptosis through down-regulation of AKT, mTOR and pI3K signaling in human gastric cancer (AGS) cells.

The phytochemicals found inCaralluma pauciflorawere studied for their ability to reduce silver nitrate in order to synthesise silver nanoparticles (AgNPs) and characterise their size and crystal structure. Thunbergol, 1,1,6-trimethyl-3-methylene-2-(3,6,9,13-tetram, Methyl nonadecanoate, Methyl cis-13,16-Docosadienate, and (1R,4aR,5S)-5-[(E)-5-Hydroxy-3-methylpent were the major compounds identified in the methanol extract by gas chromatography-mass spectrum analysis. UV/Vis spectra, Fourier-transform infrared spectroscopy, x-ray diffraction, scanning electron microscope with Energy Dispersive Xâray Analysis (EDAX), Dynamic Light Scattering (DLS) particle size analyser and atomic force microscope (AfM) were used to characterise theCaralluma paucifloraplant extract-based AgNPs. The crystal structure and estimated size of the AgNPs ranged from 20.2 to 43 nm, according to the characterization data. The anti-cancer activity of silver nanoparticles (AgNPs) synthesised fromCaralluma paucifloraextract. The AgNPs inhibited more than 60% of the AGS cell lines and had an IC50 value of 10.9640.318 g, according to the findings. The cells were further examined using fluorescence microscopy, which revealed that the AgNPs triggered apoptosis in the cells. Furthermore, the researchers looked at the levels of reactive oxygen species (ROS) in cells treated with AgNPs and discovered that the existence of ROS was indicated by green fluorescence. Finally, apoptotic gene mRNA expression analysis revealed that three target proteins (AKT, mTOR, and pI3K) were downregulated following AgNP therapy. Overall, the findings imply that AgNPs synthesised from Caralluma pauciflora extract could be used to treat human gastric cancer.

Arabincoside B isolated from Caralluma arabica as a potential anti-pneumonitis in LPS mice model.

Acute lung injury (ALI) is a life-threatening condition usually associated with poor therapeutic outcomes and a high mortality rate. Since 2019, the situation has worsened due to the COVID-19 pandemic. ALI had approximately 40% of deaths before COVID-19, mainly due to the dysfunction of the blood-gas barrier that led to lung edema, failure of gas exchange, and dyspnea. Many strategies have been taken to mitigate the disease condition, such as diuretics, surfactants, antioxidants, glucocorticoids, heparin, and ventilators with concomitant sedatives. However, until now, there is no available effective therapy for ALI. Thus, we are presenting a new compound termed Arabincoside B (AR-B), recently isolated from Caralluma arabica, to be tested in such conditions. For that, the lipopolysaccharide (LPS) mice model was used to investigate the capability of the AR-B compound to control the ALI compared to standard dexamethasone. The results showed that AR-B had a significant effect on retrieving ALI. A further mechanistic study carried out in the serum, lung homogenate, histological, and immunohistochemistry sections revealed that the AR-B either in 50 mg/kg or 75 mg/kg dose inhibited pro-inflammatory cytokines such as IL-6, IL-13, NF-κB, TNFα, and NO and stimulated regulatory cytokines IL-10. Moreover, AR-B showed a considerable potential to protect the pulmonary tissue against oxidative stress by decreasing MDA and increasing catalase and Nrf2. Also, the AR-B exhibited an anti-apoptotic effect on the lung epithelium, confirmed by reducing COX and BAX expression and upregulating Bcl-2 expression. These results pave its clinical application for ALI.

Protective Effect of Plumeria Pudica Latex Proteins on Intestinal Mucositis Induced by 5-Fluorouracil.

Intestinal mucositis is characterized by inflammation and ulceration of the mucosa that affects the gastrointestinal tract and is associated with administering some drugs, such as 5- Fluorouracil (5-FU), conventional chemotherapy used in clinics for cancer therapy. Inside intestinal mucosa, the 5-FU acts, leading to oxidative stress, stimulating the production/release of proinflammatory cytokines, local accumulation of neutrophils and consequent tissue damage. These alterations favor bacterial proliferation, triggering secondary infections, and are responsible for undesired effects such as myelosuppression and diarrhea. These factors negatively impact oncological patients' quality of life and explain why they commonly interrupt their treatment prematurely. Currently, there is no specific drug with the ability to completely avoid this condition, so the search for new molecules with pharmacological properties that can be used for preventing or ameliorating intestinal mucositis is important. Plumeria pudica is a plant that produces latexcontaining molecules with therapeutic potential. A protein fraction obtained from this latex (LPPp), which comprises a well-defined mixture of chitinases, proteinases proteinase inhibitors, was demonstrated to have antioxidant and anti-inflammatory activities, preserving tissue glutathione and malondialdehyde concentration, reducing superoxide dismutase and myeloperoxidase activity, and reducing the level of proinflammatory cytokines in different experimental models. Given this scenario, inflammation and oxidative stress are directly involved in the pathogenesis of intestinal mucositis promoted by 5-FU. So, the hypothesis is that LPPp could inhibit these factors to attenuate the cytotoxicity of this pathology associated with 5-FU-treatment. This article brings new insights into the potential of the laticifer proteins extracted from the latex of P. pudica and opens new perspectives for the treatment of this type of intestinal mucositis with LPPp.

Russelioside A, a Pregnane Glycoside from Caralluma tuberculate, Inhibits Cell-Intrinsic NF-κB Activity and Metastatic Ability of Breast Cancer Cells.

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a potential target for inflammatory-breast cancer treatment as it participates in its pathogenesis, such as tumor initiation, progression, survival, metastasis, and recurrence. In this study, we aimed to discover a novel anti-cancer treatment from natural products by targeting NF-κB activity. Using the 4T1-NFκB-luciferase reporter cell line, we tested three pregnane glycosides extracted from the herb Caralluma tuberculata and discovered that Russelioside A markedly suppressed NF-κB activity in breast cancer. Russelioside A inhibited NF-κB (p65) transcriptional activity and its phosphorylation. Following NF-κB inhibition, Russelioside A exerted anti-proliferative and anti-metastatic effects in breast cancer cells in vitro. Moreover, it inhibited the NF-κB constitutive expression of downstream pathways, such as VEGF-b, MMP-9, and IL-6 in 4T1 cells. In addition, it reduced the metastatic capacity in a 4T1 breast cancer model in vivo. Collectively, our conclusions reveal that Russelioside A is an attractive natural compound for treating triple-negative breast cancer growth and metastasis through regulating NF-κB activation.

Hepatoprotective potential of flavonoid-rich extracts from Gongronema latifolium benth leaf in type 2 diabetic rats via fetuin-A and tumor necrosis factor-alpha.

BACKGROUND: This study assessed the hepatoprotective potential of flavonoid-rich extracts from Gongronema latifolium Benth on diabetes-induced type 2 rats via Fetuin-A and tumor necrosis factor-alpha (TnF-α). METHODS: In a standard procedure, the flavonoid-rich extract was prepared. For experimental rats, streptozotocin was injected intraperitoneally (45 mg/kg body weight) to induce diabetes mellitus. Following this, rats were given 5% of glucose water for 24 h. Hence, the animals were randomly divided into five groups of ten rats each, consisting of non-diabetic rats, diabetic controls, diabetic rats treated with low and high doses of flavonoid rich-extracts from Gongronema latifolium leaf (FREGL) (13 and 26 mg/kg, respectively), and diabetic rats treated with 200 mg/kg of metformin glibenclamide orally for 3 weeks. Afterwards, the animals were sacrificed, blood and liver were harvested to evaluate different biochemical parameters, hepatic gene expressions and histological examinations. RESULTS: The results revealed that FREGL (especially at the low dose) significantly (p < 0.05) reduced alanine transaminase (ALT), aspartate aminotransferase (AST) and alkaline phosphate (ALP) activities, lipid peroxidation level, as well as relative gene expressions of fetuin-A and TNF-α in diabetic rats. Furthermore, diabetic rats given various doses of FREGL showed an increase in antioxidant enzymes and hexokinase activity, as well as glucose transporters (GLUT 2 and GLUT 4), and glycogen levels. In addition, histoarchitecture of the liver of diabetic rats administered FREGL (especially at the low dose) was also ameliorated. CONCLUSION: Hence, FREGL (particularly at a low dose) may play a substantial role in mitigating the hepatopathy complication associated with diabetes mellitus.

Caralluma tuberculata exhibits analgesic and anti-arthritic potential by downregulating pro-inflammatory cytokines and attenuating oxidative stress.

Caralluma tuberculata N.E. Brown (Common name: Chongan), belonging to the family Asclepiadaceae is distributed widely in hilly areas of Dir, Swat, Kohat and in plain lands of Punjab, Pakistan. The plant has been used as a source of vegetable as well as home remedy for headache, muscle spasms and rheumatism. The present study was proposed to investigate the analgesic, anti-inflammatory and anti-arthritic potential of the aqueous methanolic extract of C. tuberculata (ICE). The dried shoots of plant were used to prepare aqueous methanolic extract (30:70) by 3 days thrice maceration and filtration followed by evaporation under reduced pressure. ICE was screened for the presence of phytochemicals using preliminary phytochemical analysis and HPLC. The antioxidant potential was evaluated through DPPH assay. Analgesic potential of ICE was studied using hot plate and tail immersion methods, and anti-inflammatory activity was performed using turpentine oil and carrageenan-induced inflammation models, in wistar albino rats. Formaldehyde-induced and Complete Freund's Adjuvant-induced arthritis models were used for the assessment of anti-arthritic activity of ICE and its effects on serum levels of PGE-2 as well as gene expression levels of pro-inflammatory cytokines were studied. ICE displayed a dose-dependent (300-1000 mg/Kg p.o.) analgesic effect in hot plate (maximum retention time of 10.87 and 13 s) and tail immersion (response time of 11 and 13.64 s) tests at the doses of 500 and 1000 mg/Kg, respectively. The extract exhibited a significant decrease in paw inflammation of rats at the doses of 500 and 1000 mg/Kg as compared to the disease control group. ICE also exhibited a remarkable decline in arthritic score and a dose-dependent drop in serum levels of prostaglandin E2. There was a significant suppression in the expression of TNF-α, IL-1ß, IL-6, NF-κB and cyclooxygenase enzyme in treatment groups. This study concludes that Caralluma tuberculata exhibits strong analgesic, anti-inflammatory, antioxidant and anti-arthritic activities thus upholding the vernacular use of the plant for pain and rheumatism.

Ameliorative effect of flavonoid-rich extracts from Gongronema latifolium against diabetic cardiomyopathy via serpin A3 and socs3-a in streptozocin treated rats.

INTRODUCTION: The present study access the effect of the flavonoid-rich extract from Gongronema latifolium against cardiomyopathy streptozotocin-induced diabetic rats. MATERIALS AND METHODS: The flavonoid-rich extract from G. latifolium leaf (FREGL) was prepared using a standard method. Diabetes was induced by a single intraperitoneal (i.p.) injection of streptozotocin. The experimental animals were divided into five groups as non-diabetic rats, diabetic control, diabetic rats administered low and high doses of FREGL (13 and 26 mg/kg), and metformin-glibenclamide orally for 21 days. Hence, the experimental animals were sacrificed; blood and heart were harvested to determine diverse biochemical parameters, including the gene expressions of serpin A3 and socs3-a as well as histological examination. RESULTS: The results demonstrated that FREGL significantly (p < 0.05) reduced fasting blood glucose, total cholesterol, low density lipoprotein (LDL), triglyceride (TG), lipid peroxidation levels, as well as the activities of lactate dehydrogenase and creatine kinase-MB, including the relative gene expressions of serpin A3 and Socs3-A in diabetic rats. Also, diabetic rats that received different doses of FREGL showed a substantial rise in insulin and high density lipoprotein (HDL) levels, antioxidant enzyme activities, as well as, normal histoarchitecture of the heart tissues. CONCLUSION: Therefore, FREGL may be beneficial in alleviating diabetic cardiomyopathy.

Latex proteins from Plumeria pudica reduce ligature-induced periodontitis in rats.

BACKGROUND: Previous studies have shown that latex proteins from Plumeria pudica (LPPp) have anti-inflammatory and antioxidant activity. Therefore, the aim of this study was to evaluate the effects in rats of LPPp on ligature-induced periodontitis, an inflammatory disease. METHODS: The animals were divided into groups: saline (animals without induction of periodontitis), periodontitis (induced periodontitis and untreated) and LPPp (induced periodontitis and treated with 40 mg/kg). The following parameters were evaluated after 20 consecutive days of treatment: gingival bleeding index (GBI), probing pocket depth (PPD), alveolar bone height (ABH) and gingival myeloperoxidase (MPO) activity. In the hepatic tissue, malondialdehyde (MDA), glutathione (GSH) and histopathological alterations were evaluated. Blood levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured. RESULTS: Significant reduction in GBI, PPD and gingival MPO activity and ABH was seen in animals treated with LPPp compared with periodontitis. Values of GSH, MDA, ALT and histopathological evaluation were preserved in animals treated with LPPp. CONCLUSIONS: Treatment with LPPp improved clinical aspects of periodontitis, reduced the blood and hepatic alterations and prevented alveolar bone loss. Data suggest that LPPp have potential for treatment of periodontitis.

The impact of carbon source on cell growth and the production of bioactive compounds in cell suspensions of Hancornia speciosa Gomes.

Belonging to the Brazilian flora, the species Hancornia speciosa (Gomes), known as mangabeira, has bioactive compounds of interest, such as flavonoids, xanthones, and proanthocyanidins. The objective of this study was to determine how the supplementation of sugars in culture medium affects the osmotic potential of the medium, as well as its influence on cell growth and on the concentration of phenolic compounds. For this purpose, after 90 days of subculture, 20 mL aliquots of the cultures were added to flasks containing 20 mL of medium with different sugars (glucose, fructose, sucrose, mannitol, and sorbitol) under a 16-h photoperiod with a spectral range between 400 and 700 nm of photosynthetically active radiation (45-55 µmol m-2 s-1) in a shaker at 110 rpm. After 30 days, the pH, electrical conductivity, osmotic potential, biomass accumulation, and concentrations of phenolic compounds were evaluated. Regardless of their concentration in the medium, the sugars sorbitol and mannitol provided more unfavorable conditions for water absorption at the cellular level, reducing the water potential of the medium. Sucrose favored greater water absorption and biomass accumulation. Among the various sugar concentrations, 3% (30 g/L) sucrose or glucose improved the accumulation of fresh and dry cell weight and the production of polyphenols such as chlorogenic acid, epicatechin, rosmarinic acid, hesperidin, rutin, and quercetin. In addition, they resulted in a higher osmotic potential of the medium and larger cells than other carbon sources. Despite the differences in cell size, no culture conditions compromised cell survival.

The effect of an orally-dosed Caralluma Fimbriata extract on appetite control and body composition in overweight adults.

To examine the effect of a Caralluma Fimbriata extract (CFE) on biomarkers of satiety and body composition in overweight adults. A double-blind, randomised, placebo controlled trial to examine the effect of a Caralluma Fimbriata extract (CFE) on biomarkers of satiety and body composition in overweight adults. Eighty-three men and women aged between 20 and 50 years of age completed 16 weeks of daily supplementation with either CFE or placebo. Plasma cardiometabolic (lipid profile, glucose, insulin) and satiety (ghrelin, leptin, neuropeptideY) biomarkers, body composition, diet history and gastrointenstinal function were assessed at baseline, weeks 4, 8, 12 and 16. Subjects in the CFE and placebo groups were well matched and predominatly female 93% and 87.5%, with a mean age of 40.9 ± 6.7 and 39.5 ± 7.5 years and body mass index (BMI) of 30.0 ± 3.1 and 30.2 ± 2.9 kg/m2 respectively. There was a significant difference in plasma leptin concentration change between groups at week 16 (p = 0.04), with the placebo group increasing concentration (2.27 ± 4.80 ng/mL) while the CFE group (0.05 ± 4.69 ng/mL) remained the same. At week 16, the CFE group had significantly reduced their calorie intake from baseline compared to the placebo group (245 cal vs 15.8 cal respectively p < 0.01). The CFE group also had a significant reduction in waist circumference of 2.7 cm compared to an increase of 0.3 cm in the placebo group (p = 0.02). A weight increase from baseline was seen in the placebo group that was not observed in the CFE group (1.33 kg weight gain vs 0.37 kg weight loss respectively; p = 0.03). The placebo group also had a significant increase in fat mass, android fat mass, BMI and leptin compared to the CFE group (p = 0.04, 0.02, < 0.01 respectively). CFE was effective at maintaining bodyweight during a non-calorie controlled diet compared to a placebo. The mechanism responsible for this action is requiring further research and could be due to an increase in satiety receptor sensitivity.

Anticancer Cardenolides from the aerial parts of Calortopis procera.

Column chromatography (CC) analysis of methanol and butanol extracts of the aerial parts of Calortopis procera as well as the methanol extract of its latex, led to the isolation of 8 cardenolides, of which the structures were elucidated by NMR and HRESIMS spectroscopy. They also revealed several triterpenes and flavonoid glycoside. Based on the antiproliferative activity reported for cardenolides, the activity of calotropin and calotoxin was tested against two common cancer cell lines, human triple-negative breast cancer cell line (MDA-MB-231) and human lung adenocarcinoma cell line (A549). The high toxicity of the latex also encouraged performing the same test on the same cancer cell lines. The anti-proliferative activity of calotropin and calotoxin was compared to the methanol extract and the wax of the latex. The results showed that calotropin and calotoxin have significant cytotoxicity against MDA-MB-231 and A549 cell lines ranging from 0.046 to 0.072 µM compared to the methanol extract and the wax of its latex ranging from 0.47 to 58.41 µM. Moreover, the results showed lower toxicity of all treatments to the human skin fibroblasts compared to the toxicity to both MDA-MB-231 and A549 cancer cells lines except the higher toxicity of Methanolic extracts of C. procera latex to the MDA-MB-231 cells. In conclusion, C. procera is a medicinal plant with a wide spectrum of cardinolides including calotropin and calotoxin, which are promising agents for targeted cancer phytotherapy.

Tetracyclic Triterpenoids, Steroids and Lignanes from the Aerial Parts of Oxypetalum caeruleum.

The MeOH extract from dried aerial parts of Oxypetalum caeruleum (Apocynaceae) plants yielded seventeen compounds, including four new tetracyclic triterpenoids, one pregnane glycoside, two lignane glycosides, and ten known compounds. The structures of the new compounds were established using NMR, MS spectroscopic analysis and chemical evidence.

Latex Proteins from Plumeria pudica with Therapeutic Potential on Acetaminophen-Induced Liver Injury.

Liver disease is global health problem. Paracetamol (APAP) is used as an analgesic drug and is considered safe at therapeutic doses, but at higher doses, it causes acute liver injury. N-acetyl-p- Benzoquinone Imine (NAPQI) is a reactive toxic metabolite produced by biotransformation of APAP. NAPQI damages the liver by oxidative stress and the formation of protein adducts. The glutathione precursor N-acetylcysteine (NAC) is the only approved antidote against APAP hepatotoxicity, but it has limited hepatoprotective effects. The search for new drugs and novel therapeutic intervention strategies increasingly includes testing plant extracts and other natural products. Plumeria pudica (Jacq., 1760) is a plant that produces latex containing molecules with therapeutic potential. Proteins obtained from this latex (LPPp), a well-defined mixture of chitinases, proteinases proteinase inhibitors have shown anti-inflammatory, antinociceptive, antidiarrheal effects as well as a protective effect against ulcerative colitis. These studies have demonstrated that LPPp acts on parameters such as Glutathione (GSH) and Malondialdehyde (MDA) concentration, Superoxide Dismutase (SOD) activity, Myeloperoxidase (MPO) activity, and TNF- α IL1-ß levels. Since oxidative stress and inflammation have been reported to affect the initiation and progression of liver injury caused by APAP, it is suggested that LPPp can act on aspects related to paracetamol hepatoxicity. This article brings new insights into the potential of the laticifer proteins extracted from the latex of P. pudica and opens new perspectives for the treatment of this type of liver disease with LPPp.

Consumption of Gongronema latifolium Aqueous Leaf Extract During Lactation May Improve Metabolic Homeostasis in Young Adult Offspring.

BACKGROUND AND OBJECTIVE: Medicinal plants constitute a fundamental component of the traditional healthcare system in rural communities throughout Africa and Gongronema latifolium (GL), is widely trusted in Nigeria to have strong nutritional and medicinal values. This study was done to determine the effect of maternal consumption of GL during lactation in young adult offspring. MATERIALS AND METHODS: Twenty four female albino Wistar rats were used for this study and were randomly assigned to four (4) groups. Group I: Control, Group II, 100 mg kg-1, III, 200 mg kg-1 and IV: 400 mg kg-1 at delivery. The extract was administered orally and daily throughout lactation. RESULTS: At postnatal day 42, offspring of extract-treated groups showed a dose-related significant decrease (p<0.05) in body weight, food intake, glucose, total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C) and a significant increase in liver weight index, pancreatic weight index, high-density lipoprotein cholesterol (HDL-C) and insulin concentrations of the offspring when compared with control in both sexes. Histological examination showed that GL extract caused histological alterations of the liver structures with various changes in the size of the sinusoids, with mild inflammatory cells without hepatotoxicity and cellular multiplication when compared with control. CONCLUSION: This study suggested that consumption of GL extract by lactating dams may improve metabolic homeostasis in young adult offspring.

Natural bioactive 4-Hydroxyisophthalic acid (4-HIPA) exhibited antiproliferative potential by upregulating apoptotic markers in in vitro and in vivo cancer models.

There is tremendous scope for identifying novel anti-cancer molecules from the unexplored reserves of plant kingdom. The application of dietary supplementation or medicine derived from such sources is a promising approach towards treatment of cancer. In the present study we have evaluated the antiproliferative potential of 4-hydroxyisophthalic acid (4-HIPA), which is a novel antioxidant compound isolated from the roots of the aqueous extract of Decalepis hamiltonii. 4-HIPA was screened in vitro against human breast cancer cell lines MCF-7, MDA-MB-468 and normal human breast epithelial cell MCF-10, and demonstrated that human breast cancer cell lines, in contrast to MCF-10, are sensitive to 4-HIPA .4-HIPA showed marked reduction in cell viability and short-term proliferation assays in these cells. Results of the long-term colony formation and scratch assay further reaffirmed that 4-HIPA inhibited the growth and proliferation in breast cancer cells. We further conducted in vivo studies using murine Ehrlich Ascites Tumor (EAT) cell model. Our in vivo results established that treatment with 4-HIPA reduced the tumorigenesis by promoting apoptosis in EAT-bearing mice. The results of our molecular docking predictions further warranted our claim. This study is valuable as 4-HIPA exhibits antiproliferative potential that can be exploited in the development of anticancer drugs.

A Biolistic-Mediated Virus-Induced Gene Silencing in Apocynaceae to Map Biosynthetic Pathways of Alkaloids.

Monoterpene indole alkaloids (MIAs) are specialized metabolites synthesized in many plants of the Apocynaceae family including Catharanthus roseus and Rauvolfia sp. MIAs are part of the chemical arsenal that plants evolved to face pet and herbivore attacks, and their high biological activities also confer pharmaceutical properties exploited in human pharmacopeia. Developing robust and straightforward tools to elucidate each step of MIA biosynthetic pathways thus constitutes a prerequisite to the understanding of Apocynaceae defense mechanisms and to the exploitation of MIA cytotoxicity through their production by metabolic engineering. While protocols of virus-induced gene silencing (VIGS) based on Agrobacterium-based transformation have emerged, the recalcitrance of Apocynaceae to this type of transformation prompted us to develop an universal procedure of VIGS vector inoculation. Such procedure relies on the delivery of the transforming plasmids through a particle bombardment performed using a biolistic device and offers the possibility to overcome host specificity to silence genes in any plant species. Using silencing of geissoschizine oxidase as an example, we described the main steps of this biolistic mediated VIGS in C. roseus and R. tetraphylla.

Parameritannin A-2 from Urceola huaitingii enhances doxorubicin-induced mitochondria-dependent apoptosis by inhibiting the PI3K/Akt, ERK1/2 and p38 pathways in gastric cancer cells.

Parameritannin A-2 (PA-2) is a natural product extracted from the stems of the plant Urceola huaitingii. Our previous studies have shown that PA-2 exhibits significant synergistic anticancer effects with doxorubicin (DOX) in HGC27 gastric cancer cell lines. Here we report that our isobolographic analysis confirms the synergistic cytotoxic effects of PA-2 and DOX in HGC27 cells. Flow cytometry and immunoblotting indicate that PA-2 enhances DOX-mediated apoptosis. Importantly, PA-2 enhances the intracellular accumulation of DOX in HGC27 cells. The combination of DOX and PA-2 remarkably increases the release of cytochrome C and the activation of caspase-3 and caspase-9, compared with DOX treatment alone. Moreover, PA-2 attenuates the DOX-induced activation of Akt, ERK1/2 and p38 signaling pathways, providing a molecular mechanism for the synergistic effects of DOX and PA-2 in the induction of apoptosis. In conclusion, our studies demonstrate that PA-2 and DOX synergistically induce mitochondria-dependent apoptosis as PA-2 inhibits the PI3K/Akt, ERK1/2 and p38 pathways in HGC27 cells. These findings suggest that the combination treatment with PA-2 and DOX may represent a potent therapy for gastric cancer.

High-throughput metabolomic and transcriptomic analyses vet the potential route of cerpegin biosynthesis in two varieties of Ceropegia bulbosa Roxb.

MAIN CONCLUSION: Exploration with high-throughput transcriptomics and metabolomics of two varieties of Ceropegia bulbosa identifies candidate genes, crucial metabolites and a potential cerpegin biosynthetic pathway. Ceropegia bulbosa is an important medicinal plant, used in the treatment of various ailments including diarrhea, dysentery, and syphilis. This is primarily attributed to the presence of pharmaceutically active secondary metabolites, especially cerpegin. As this plant belongs to an endemic threatened category, genomic resources are not available hampering exploration on the molecular basis of cerpegin accumulation till now. Therefore, we undertook high-throughput metabolomic and transcriptomic analyses using different tissues from two varieties namely, C. bulbosa var. bulbosa and C. bulbosa var. lushii. Metabolomic analysis revealed spatial and differential accumulation of various metabolites. We chemically synthesized and characterized the cerpegin and its derivatives by liquid chromatography tandem-mass spectrometry (LC-MS/MS). Importantly, these comparisons suggested the presence of cerpegin and 5-allyl cerpegin in all C. bulbosa tissues. Further, de novo transcriptome analysis indicated the presence of significant transcripts for secondary metabolic pathways through the Kyoto encyclopedia of genes and genomes database. Tissue-specific profiling of transcripts and metabolites showed a significant correlation, suggesting the intricate mechanism of cerpegin biosynthesis. The expression of potential candidate genes from the proposed cerpegin biosynthetic pathway was further validated by qRT-PCR and NanoString nCounter. Overall, our findings propose a potential route of cerpegin biosynthesis. Identified transcripts and metabolites have built a foundation as new molecular resources that could facilitate future research on biosynthesis, regulation, and engineering of cerpegin or other important metabolites in such non-model plants.

Melocochines A and B, Two Alkaloids from the Fruits of Melodinus cochinchinensis.

Melocochines A (1) and B (2), one pair of epimers with an unprecedented skeleton, were isolated from Melodinus cochinchinensis. Their structures and absolute configurations were established by a combination of MS, NMR, and single-crystal X-ray diffraction analyses. Compounds 1 and 2 represent a class of novel alkaloids, characterized by a rare 1H-benzo[b]azepane ring system within monoterpenoid indole alkaloid categories. Compounds 1 and 2 enhanced lysosomal biogenesis with LysoTracker staining intensities of 139.7% and 119.0%, respectively.