Cytotoxic steroids from the stems of Strophanthus divaricatus.

Phytochemical investigation on the stems of Strophanthus divaricatus led to the isolation of four undescribed cardiac glycosides and one undescribed C21 pregnane, together with eleven known steroids. Their structures were elucidated by a comprehensive analysis of HRESIMS, 1D and 2D NMR spectra. The absolute configuration of 16 was determined by comparison of the experimental and computed ECD spectra. Compounds 1-13 and 15 displayed potent to significant cytotoxicity against human cancer cell lines K562, SGC-7901, A549 and HeLa with IC50 values of 0.02-16.08, 0.04-23.13, 0.06-22.31 and 0.06-15.13 µM, respectively.

An in-depth look into a well-known herbal drug: Fingerprinting, isolation, identification, and content estimation of saponins in different Strophanthus seeds.

Seeds of Strophanthus species are known as a source of rapid-acting cardenolides. These water-soluble glycosides are listed as the sole critical constituents of this raw herbal drug. A non-standard cardioprotective medication with ouabain-containing oral remedies has become popular in Europe as a result of the withdrawal of corresponding registered drugs from the market. However, the bioequivalence of pure ouabain solutions, tinctures, and home-made extracts from Strophanthus seeds is unknown. Thus, this study aimed to update the information on the composition of Strophanthus seeds used for this purpose. The distribution of two main saponins and about 90 previously unreported compounds, tentatively identified as saponins in eleven Strophanthus species, was systematically evaluated by ultra-high-performance liquid chromatography mass spectrometry (UHPLC-MS) and -MS/MS. Seeds of S. gratus were selected to isolate the dominant unreported triterpenoids, bidesmosides of echinocystic and oleanolic acid. Their structures were established by HRMS, MS/MS, as well as by NMR techniques. The total saponin content, estimated by UHPLC-MS, was up to 1%. The detected saponins could influence the peroral bioavailability of hardly absorbable Strophanthus cardenolides and exhibit their own activity. This finding may be relevant when Strophanthus preparations (containing both saponins and cardiac glycosides) are used, particularly when homemade preparations are administered.

Sub-chronic toxicological evaluation of Strophanthus hispidus DC (Apocynaceae) aqueous root extract.

OBJECTIVES: Strophanthus hispidus DC (Apocynaceae) has gained wide and extensive applications in herbal medicine in Africa for the treatment of quite a lot of diseases. Owing to the extensive application and the propensity of persistent consumption of this shrub, this research investigates the sub-chronic toxicological effect of aqueous root extract of S. hispidus (SHP) in laboratory animals (rats). METHODS: The rats were allotted into four groups of eight rats each (n=8) and orally treated daily for ninety (90) days with SHP extract at 100, 500 and 1,000 mg/kg and the control group received distilled water (10 mL/kg). The rats were weighed at 15 days interval. After 90 days daily oral administration of SHP extract, blood samples were collected from the rats into lithium heparin and EDTA bottles for biochemical and haematological analysis respectively. Vital organs were weighed and histological examination was performed on the liver and kidney. RESULTS: The SHP extract displayed no significant (p>0.05) alterations in body weight of treated compared to control rats. At doses of 500 and 1,000 mg/kg, SHP-treated rats showed significant (p<0.05) increase in white blood cell (WBC), without significant difference in other haematological parameters. Non-significant (p>0.05) decrease in urea and non-significant (p>0.05) increase Na+, K+ and blood urea nitrogen (BUN) were observed. Significant (p<0.05) decrease in liver weight was observed without any alteration in the architecture of the liver and other organs investigated. CONCLUSIONS: Aqueous root extract of S. hispidus demonstrated a good safety profile in rats. Therefore, S. hispidus is harmless and safe following sub-chronic oral administration.

Evaluation of in-vitro and in-vivo antidiabetic, antilipidemic and antioxidant potentials of aqueous root extract of Strophanthus hispidus DC (Apocynaceae).

Background Antidiabetic activity of aqueous root extract of Strophanthus hispidus (SHP) was evaluated based on its folklore used in traditional medicine for the treatment of diabetes. Objectives: This study aimed to investigate the in-vitro and in-vivo antidiabetic potential of the aqueous root extract of SHP. Methods SHP (50, 100 and 200 mg/kg p.o.), glibenclamide (5 mg/kg p.o.), normal saline (10 mL/kg; diabetic control) and distilled water (10 mL/kg; normal control) were administered once daily for 28 days, with the measurement of fasting blood glucose level at 7 days interval. Blood samples were collected on day 28 for serum biochemical (albumin, total protein [TP], creatinine, alanine transaminase [ALT], aspartate transaminase [AST], alkaline phosphatase [ALP], triglycerides [TG], total cholesterol [TC], high-density lipoprotein [HDL], low-density lipoprotein [LDL], bilirubin and urea) and hematological assays. The in-vitro antidiabetic activity was investigated using α-amylase and α-glucosidase enzymes inhibitory assays. Results SHP produced a day-dependent reduction in glucose level. Peak reduction (82.94 %; p < 0.05) was produced at the dose of 100 mg/kg. SHP significantly (p < 0.05) increased the level of HDL and TP but significantly (p < 0.05) reduced the levels of TG, LDL, TC, AST, ALT, ALP, bilirubin, creatinine and urea compared with diabetic control rats. Furthermore, SHP significantly (p < 0.05) increased the level of catalase, superoxide dismutase and reduced glutathione compared to diabetic control rats. SHP significantly (p < 0.05) inhibited α-amylase and α-glucosidase enzymes compared with acarbose. Conclusion The findings in this study showed that SHP possesses beneficial antidiabetic activity.

Adonis sp., Convallaria sp., Strophanthus sp., Thevetia sp., and Leonurus sp. - Cardiotonic Plants with Known Traditional Use and a Few Preclinical and Clinical Studies.

Plants have been always a fruitful source of active metabolites against many human disorders, where cardiovascular (CV) diseases have been one of the major health problems all over the world. There are some clinically proved medicinal plants with cardioprotective effects such as Crataegus monogyna and C. oxyacantha (hawthorn) from Rosaceae. On the other hand, cardiac glycosides, present in a number of plant species, are wellknown for their cardiotonic activity. However, we encountered such a fact that very less number of studies are available on the source plants; e.g. Adonis vernalis, Convallaria majalis, Strophanthus kombe, Thevetia peruviana, Leonurus cardiaca, etc. Consequently, we herein aimed to cover all available data consisting of in vitro, in vivo, and human studies (if any) on cardiotonic effects of the aforementioned species through a wide literature search using Scopus, Web of Science as well as Pubmed.

Comparative Excito-Repellency of Three Cambodian Plant-Derived Extracts Against Two Mosquito Vector Species, Aedes aegypti and Anopheles minimus.

A study of the behavioral responses of Aedes aegypti and Anopheles minimus to 3 Cambodian plant extracts at 3 different concentrations (1%, 2.5%, and 5%) was performed using an excito-repellency test system. These 3 plants were Strophanthus scandens, Capparis micracantha, and Dioscorea hispida, selected according to traditional healer's knowledge, bibliographic studies and market surveys. Results showed that S. scandens leaves' hexane extract was the only one to exert repellency against Ae. aegypti with 23.3% of escaped mosquitoes at a concentration of 5%. Capparis micracantha was responsible for an irritant activity against An. minimus with 20.2% of escaped mosquitoes at a concentration of 2.5% and 22.8% escaping at a concentration of 5%. Dioscorea hispida showed an irritant activity on both mosquito species with 23.2% of escaped Ae. aegypti at a concentration of 5% and about 20% of escaped An. minimus at 2.5% and 5%. This is the first report on the irritant and repellent activities of S. scandens , D. hispida , and C. micracantha against mosquito species.

Effect of extraction, microbial fermentation and storage on the cardenolide profile of Strophanthus kombé Oliv. seed preparations.

Strophanthus extracts containing cardioactive cardenolides are still applied in European complementary medicine for the treatment of heart diseases. However, the cardenolide profile and the fate of individual compounds during extraction and storage are not well understood. Therefore, the objective of the present study was to characterize the cardenolide compound pattern in extracts of different polarity and their structural changes upon storage in aqueous fermented preparations. For this purpose, individual cardenolides were quantitated by a UHPLC-DAD validated method using an internal standard. Three different extraction protocols were compared: hydroethanolic extraction under reflux with and without previous defatting of the seed material and ultrasonic-assisted extraction at ambient temperature. Reflux extraction of non-defatted seeds showed maximum cardenolide yields. Differences in the cardenolide contents of seeds of the different origins Zimbabwe and Malawi were observed. The cardenolide profile and metabolization of individual compounds upon fermentation and storage of S. kombé seed extracts revealed that predominant cardenolides, mainly strophanthidin glycosides, changed upon storage over 12 months. Cardenolides exhibiting two or three saccharide moieties were degraded presumably by ß-glucosidase activities, originating from the plant material or lactobacilli, releasing the corresponding monoglycosides. The latter were further degraded into the corresponding aglycones probably by acid hydrolysis as a result of lactic acid accumulation.

Glycosylation of trans-Resveratrol by Cultured Plant Cells under Illumination of LEDs.

Incubation of cultured cells of Strophanthus gratus with trans-resveratrol gave its 4'-O-ß-D-glucoside as the major product in addition to its 3-O-ß-D-glucoside under white and red light-emitting diodes (LEDs). Use of blue LEDs as light sources for biotransformation of trans-resveratrol much improved the yield of its ß-D-glycosides and changed the composition of products, that is, 3-O-ß-D-glucoside was the major product and 4'-O-ß-D-glucoside was the minor one.

Characterization of the cardiac glycoside and lipid profiles of Strophanthus kombé Oliv. seeds.

The seeds of Strophanthus kombé Oliv. are known to contain high levels of cardioactive compounds. However, the therapeutic use of Strophanthus in the treatment of cardiopathy requires more detailed knowledge of the compound profile to profit from the full potential of Strophanthus preparations. Therefore, the objective was to characterize the cardenolide profile and lipophilic constituents in S. kombé seeds using methods applicable in routine quality control. Freshly prepared S. kombé seed extracts were analyzed without previous sample clean-up using a novel HPLC-DAD-MSn method. In addition, seed oils were analyzed by GC-MS following derivatization of the lipids. More than 20 cardenolides were tentatively assigned in the seed extracts including strophanthidin, strophanthidol, periplogenin and strophanthidinic acid aglycones, carrying various saccharide moieties. The findings revealed the presence of eight novel cardenolides, which have not been described for S. kombé so far. The occurrence of strophanthidinic acid derivatives was verified by comparison with synthesized strophanthidinic acid-cymaropyranoside. GC-MS characterization of the oils mainly revealed the presence of fatty acids, especially oleic acid and linoleic acid, as well as phytosterols, the latter representing intermediates of cardenolide biosynthesis. In summary, these findings broaden our knowledge on the secondary metabolism of Strophanthus.

Antinociceptive, anti-inflammatory and antiulcerogenic activities of ethanol root extract of Strophanthus hispidus DC (Apocynaceae).

BACKGROUND: Strophanthus hispidus DC (Apocynaceae) is a medicinal plant widely used in traditional African medicine in the treatment of rheumatic afflictions, ulcer, conjunctivitis, leprosy and skin diseases. This study sought to investigate the antinociceptive, anti-inflammatory and antiulcer properties of the ethanol root extract of S. hispidus. METHODS: Antinociceptive activity was evaluated using acetic acid-induced writhing and formalin tests in mice. The carrageenan- and egg albumin-induced rat paw edema tests were used to investigate the anti-inflammatory actions, whereas the antiulcer activity was investigated using ethanol-, HCl- and pyloric ligation-induced gastric ulcer models in rats. RESULTS: S. hispidus [100-800 mg/kg orally (po)] produced significant (p<0.05) inhibition of writhing reflex with peak effect of 74.13% inhibition observed at 800 mg/kg. Similarly, S. hispidus significantly (p<0.05) attenuated formalin-induced early and late phase of nociception with peak effect of 61.84% and 89.43%, respectively, at 200 mg/kg. S. hispidus (25-800 mg/kg po) caused significant (p<0.05) inhibition of edema development in the carrageenan and egg albumin models with peak effect (93.40% and 90.10% inhibition of edema formation) observed at 50 mg/kg. With respect to antiulcer activity, S. hispidus (100-800 mg/kg) showed potent antiulcer activity with respective peak effects of 96% (ethanol-induced), 99% (HCl-induced) and 70.60% inhibition of ulcer. CONCLUSIONS: The findings in this study suggest that the ethanol root extract of S. hispidus possesses antinociceptive, anti-inflammatory and antiulcerogenic activities. This justifies the use of the extract in folklore medicine for the treatment of ulcer and inflammatory disorders.

Glycosylation of trans-resveratrol by plant-cultured cells.

Plant-cultured cells of Catharanthus roseus converted trans-resveratrol into its 3-O-ß-D-glucopyranoside, 4'-O-ß-D-glucopyranoside, 3-O-(6-O-ß-D-xylopyranosyl)-ß-D-glucopyranoside, and 3-O-(6-O-α-L-arabinopyranosyl)-ß-D-glucopyranoside. The 3-O-(6-O-ß-D-xylopyranosyl)-ß-D-glucopyranoside and 3-O-(6-O-α-L-arabinopyranosyl)-ß-D-glucopyranoside compounds of trans-resveratrol are both new. Incubation of plant-cultured cells of Ipomoea batatas and Strophanthus gratus with trans-resveratrol gave trans-resveratrol 3-O-ß-D-glucopyranoside and trans-resveratrol 4'-O-ß-D-glucopyranoside.

Cytotoxic cardenolide glycosides of Roupellina (Strophanthus) boivinii from the Madagascar rainforest.

Bioassay-guided fractionation of an ethanol extract of Roupellina (Strophanthus) boivinii from the rainforest of Madagascar afforded the six new cardenolide glycosides boivinides 1-6, as well as the four known cardenolide glycosides digitoxigenin 3-O-[beta-D-glucopyrananosyl-(1-->4)-alpha-L-acofriopyranoside], corotoxigenin 3-O-beta-D-boivinoside, 17alpha-corotoxigenin 3-O-beta-D-sarmentoside, and uzarigenin 3-O-alpha-L-rhamnoside. The structures of these compounds were elucidated by various 1D and 2D NMR techniques. All new compounds showed significant antiproliferative activity against the A2780 human ovarian cancer cell line, with boivinide A being the most active at IC50 = 0.17 microM.

[Ouabain: from an arrow poison to a new steroidal hormone]. / Ouabaín--od sípového jedu k novému steroidnému hormónu.

For more than 200 years, cardiotonic glycosides have been used for the treatment of congestive heart failure. Ouabain is a well-known arrow poison obtained from different Acokanthera or Strophanthus species. Much information has now accumulated that this plant toxin and its congeners are mammalian steroid hormones involved in the pathophysiology of cardiovascular diseases. There is an interesting fact that 50% patients with essential hypertension have elevated levels of endogenous ouabain. A better knowledge of the interactions of these compounds with the hormones of salt and water metabolism might help to improve the diagnosis and therapy of hypertension.

Mutual information and the homeopathic effect.

We explore the feasibility of using mutual information to characterize the homeopathic effect. This quantity measures the information gained about a signal at time (t + tau), from its value at an earlier time t; it quantifies the predictability of data. We illustrate our method with an analysis of the homeopathic effect of Strophanthus hispidus on the cardiac rhythm of healthy human subjects, using data from a previous experiment. Our results allow an intuitively clear rendering and agree with the similitude principle applied to this case. They also show that the solvent has a significant effect on the signal; hence, it does not act as an ideal placebo and we discuss some therapeutic corollaries to this observation.