New Saponins fromPhytolacca dodecandra l'HERIT

Hedyocoronins A and B: two new oleanane saponins from the aerial parts of Hedyotis coronaria

Two new oleanane saponins, hedyocoronin A (1) and hedyocoronin B (2), were isolated from the aerial parts of Hedyotis coronaria (Kurz) Craib, Rubiaceae, collected at Da Oai district, Lam Dong province in Vietnam. Their chemical structures were elucidated by HR-MS, 1D and 2D-NMR spectra, along with the comparison with those reported in the literature. Compounds 1 and 2 showed weak cytotoxicity against KB and HeLa-S3 cancer cell lines with IC₅₀ values of more than 54 µM.

Triterpenoid and Saponin Rich Phytolacca dodecandra L'Herit (Endod): A Review on Its Phytochemistry and Pharmacological Properties

Phytolacca dodecandra L'Herit (Endod) is the most extensively studied plant among 35 known species in the genus Phytolacca (Family: Phytolaccaceae). The plant has been used as a viable treatment for various ailments, such as malaria, rabies, ascariasis, and skin disorders, in many parts of Africa. In Ethiopia, the dried and powdered Endod berries have been used for a long period of time as a detergent to clean clothes. Since the discovery of the molluscicidal activities of its berries more than five decades ago, P. dodecandra has been a research focus worldwide and several phytochemicals mainly of triterpenoids and saponins were reported. Additionally, various biological activities, including larvicidal, insecticidal, antibacterial, antifungal, and anti-inflammatory activities of its isolated compounds and crude extracts were investigated. Furthermore, some of the findings from pharmacological and phytochemical investigations were patented to be used in various medicinal formulations. The plant is still the subject of many investigations and hence, a thorough up-to-date review is required to provide comprehensive information needed for future exploitation of the plant. In this review, the phytochemical compositions and pharmacological activities are comprehensively addressed and discussed in details.

Phytolacca dodecandra (Phytolaccaceae) Root Extract Exhibits Antioxidant and Hepatoprotective Activities in Mice with CCl4-Induced Acute Liver Damage

BACKGROUND

The liver is a hub of metabolism and detoxification of substances. Since many redox reactions take place in the liver, it is prone to oxidative damage. Unlike conventional agents, botanicals act through several mechanisms in preventing oxidative damage. Among these Phytolacca dodecandra is the most commonly used agent in Ethiopian folk medicine.

OBJECTIVE

To evaluate antioxidant and hepatoprotective activities of the 80% methanol extract of P. dodecandra root.

METHODS

Male mice were divided into six groups and treated accordingly. Negative control was given 2% Tween 80, toxicant control administered with carbon tetrachloride (CCl4), positive control treated with silymarin 100 mg/kg, and test groups were treated with 100, 200, and 400 mg/kg of the extract. Then, serum levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, albumin, total protein, and bilirubin were determined. Determination of the change in body weight and liver weight, histopathologic examination of the liver, and in vitro and in vivo antioxidant assays were also carried out.

RESULTS

The levels of ALP, ALT, AST, GGT, LDH, and bilirubin were significantly reduced, while albumin and total protein were significantly increased after treatment with P. dodecandra root extract at the doses of 200 and 400 mg/kg in CCl4 intoxicated mice. Cholesterol metabolism and lipoprotein synthesis capabilities of the liver of mice were also returned to normal in the two doses. Besides, the 200 and 400 mg/kg doses were able to return the normal architecture and morphology of hepatocytes. Furthermore, the plant extract was found to scavenge free radicals in vitro and inhibit lipid peroxidation in vivo.

CONCLUSION

The results suggest that the 80% methanol extract of P. dodecandra root can be used for the management of liver disease.

Chemical Composition and Antimicrobial Activity of Essential Oil from Phytolacca dodecandra Collected in Ethiopia

The essential oil from Phytolacca dodecandra, a traditional herb of Ethiopia, has been studied, including the chemical composition and antimicrobial activity. The difference between four P. dodecandra samples (P-1–P-4), which differed in gender or location, has also been analyzed. The essential oils were obtained by steam distillation, while the aromas were extracted by head space solid-phase microextraction (HS-SPME) and both were analyzed by gas chromatography- mass spectrometry (GC-MS). The oils’ antimicrobial activities were evaluated by the microdilution method against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida albicans. Ninety one components, representing 88.37 to 94.01% of the aromas, were identified. The compositions of the aromas of four samples are mainly dominated by aldehydes and ketones: 2-nonanone (1.80–30.80%), benzaldehyde (4.99–25.99%), and sulcatone (2.34–5.87%). Sixty components representing 64.61 to 69.64% of the oils were identified, and phytone (3.04–21.23%), phytol (4.11–26.29%) and palmitic acid (1.49–23.87%) are the major compounds. No obvious antimicrobial activity was observed for all the four essential oils.

Decades of Phytochemical Research on African Biodiversity

This review provides a panoramic view of Prof. Kurt Hostettmann's contribution to the study of African medicinal plants as documented in over 85 publications with collaborators from about a dozen African countries. Many novel bioactive secondary metabolites were isolated, their structures elucidated by hyphenated HPLC techniques and their biological activity determined.

Molluscicidal saponins from Phytolacca icosandra

Five monodesmosidic serjanic acid saponins and a monodesmosidic spergulagenic acid saponin were isolated from an aqueous extract of the berries of Phytolacca icosandra. A methanol extract of the berries furnished three bidesmosidic serjanic acid glycosides. Their structures were established by spectroscopic (ES-MS, 1H NMR, COSY, HSQC, HMBC, 13C NMR) and chemical methods. The molluscicidal, spermicidal and haemolytic properties of the saponins were investigated.

Control of water-borne parasitic diseases with natural products: the potential of Dialium guineense as a molluscicide

The molluscicidal activity of the fruit and leaves of Dialium guineense was found to be due to glycosides of the triterpenoid oleanolic acid. Three glycosides were isolated from the fruit and a fourth from the leaves and are known compounds. The amount of total saponins present in D. guineense makes it a good candidate for a readily available molluscicide in Nigerian villages.

Hederagenin glycosides from Pometia eximia

Seven new saponins, all glycosides of hederagenin (3 beta,23- dihydroxyolean-12-en-28-oic acid), were isolated from the stem of Pometia eximia along with hederagenin and two known saponins. Their structures were established as 28-O-beta-D-apiosyl(1-->2)-beta-D-glucopyranosyl-, 3-O-alpha-L- arabinofuranosyl(1-->3)[alpha-L-rhamnopyranosyl (1-->2)]-beta-D- xylopyranosyl-, 3-O-beta-D-apiosyl(1-->3)[alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-, 3-O-alpha-L-arabinofuranosyl(1-->3)[alpha-L-rhamnopyranosyl- (1-->2)]-beta-L-arabinopyranosyl-, 3-O-beta-D-xylopyranosyl(1-->3)[alpha-L- rhamnopyranosyl(1-->2)]-alpha-L-arabinopyranosyl-, 3-O-beta-D-xylopyranosyl-(1-->3)[alpha-L-rhamnopyranosyl(1-->2)]-beta-D- glucopyranosyl-, 3-O-beta-D-galactopyranosyl(1-->3)[alpha-L-rhamnopyranosyl(1-->2)]-beta- D- glucopyranosyl-hederagenins.

Molluscicidal saponins from Catunaregam nilotica

Two new saponins were isolated from the fruits of Catunaregam nilotica Stapf, syn. Lachnosiphonium nilotica; Randia nilotica; Xeromphis nilotica. Their structures were determined mainly by spectroscopic methods as 3- O-[O-alpha-L-rhamnopyranosyl-(1-->3)-O-[O-beta-D-glucopyranosyl-(1 -->3)]- beta-D-glucopyranosyl]oleanolic acid and 28-O-beta-D- glucopyranosyl-3-O-[O-alpha-L-rhamnopyranosyl-(1-->3)-O[O-beta-D- glucopyranosyl]-beta-D-glycopyranosyl]oleanolate. The monodesmosidic saponin is a potent molluscicide against the schistosomiasis transmitting snail Biomphalaria glabrata with a LC50 value of 3 ppm. In addition two known saponins, 3-O-[2', 3'-di-O-(beta-D-glucopyranosyl)-beta-D- glucopyranosyl]oleanolic acid and 3-O-[O-beta-D-glucopyranosyl(1-->3)- beta-D-glucopyranosyl]oleanolic acid, were identified and their molluscicidal activity determined, the LC50 values being 26 and 3 ppm, respectively. Initial molluscicidal screening of the crude water and ethanol extracts revealed 100% snail mortality at concentrations of 100 and 50 ppm, respectively. The haemolytic activity of the molluscicidal saponins was determined as well and the HC50 values towards bovine erythrocytes found to be 3 ppm for the new saponin, and 16 and 2 ppm, respectively, for the two known saponins.

Molluscicidal saponins from a Zimbabwean strain of Phytolacca dodecandra

Three new monodesmosidic saponins, all glycosides of 2 beta-hydroxyoleanolic acid, were isolated from an aqueous extract of a Zimbabwean strain of Phytolacca dodecandra. Their structures were, mainly by spectroscopic methods (LSIMS, 1H NMR, COSY, NOESY, TOCSY, J-resolved 1H NMR, 13C NMR, HETCOR), established as 3-O-[2',4'-di-O-(beta-D-glucopyranosyl)-beta-D-glucopyranosyl]2 beta-hydroxyoleanolic acid, 3-O-[O-alpha-L-rhamnopyranosyl-(1-->2)-O-[beta-D-galactopyranosyl- (1-->3)]-beta-D-glucopyranosyl]2 beta-hydroxyoleanolic acid and 3-O-[3'-O-(beta-D-galactopyranosyl)-beta-D-glucopyranosyl]2 beta-hydroxyoleanolic acid. Two of the saponins were submitted to a preliminary screening for molluscicidal activity against the schistosomiasis transmitting snail Biomphalaria glabrata and showed, respectively, strong and weak activity. In addition, four saponins previously reported from other strains of Phytolacca dodecandra were identified.

Search for antifungal, molluscicidal and larvicidal compounds from African medicinal plants

African medicinal plants provide a rich source of biologically-active natural products. By the use of simple bioassays in conjunction with an approach involving bioactivity guided fractionation, it is possible to isolate novel compounds with interesting properties. Several hundred plant extracts have been submitted to different screens, including bioautography on TLC plates with the fungi Cladosporium cucumerinum and Candida albicans. Among the other test systems are a bioassay for molluscicidal activity with the schistosomiasis-transmitting snail Biomphalaria glabrata and a benchtop assay for larvicidal activity with larvae of the mosquito Aedes aegypti, the vector of yellow fever. Using a variety of modern separation techniques, a number of compounds with activity in these bioassays have been isolated. These include prenylated xanthones, tetracyclic phenols and saponins. The role of saponins and saponin-containing plants in the control of schistosomiasis is outlined.

Endod: safety evaluation of a plant molluscicide

Toxicity tests, in accordance with the Minimal Data Requirements (Tier 1) of the OECD Guidelines for Pre-Market Chemicals, were conducted on a standard extract (Endod-S) from the unripe berries of Phytolacca dodecandra, a potent botanical molluscicide of potential importance in the control of schistosomiasis. In acute mammalian toxicity tests, except for the eye irritation toxicity test which indicated severe irritancy, all test results were classified as either nontoxic or slightly toxic. Eye protection is therefore recommended during berry crushing and handling of dry powders. Ecotoxicity tests indicated that Endod is no more toxic than currently recommended synthetic molluscicides; however, environmental fate and additional local ecotoxicity tests are recommended for nontarget aquatic organisms present in the endemic situations of field trials. Given these toxicological data and recognizing the need for an affordable, locally cultivated, botanical molluscicide, it is concluded that field trials of Endod in schistosomiasis control are now justifiable.

Plants used in traditional medicine in eastern Tanzania. V. Angiosperms (Passifloraceae to Sapindaceae)

Sixty-one Angiosperms (Passifloraceae to Sapindaceae) are listed, which are used by traditional healers in five regions of Eastern Tanzania, namely, Coast, Dar es Salaam, Kilimanjaro, Morogoro and Tanga. For each species listed, the botanical name, vernacular name, collection number, locality, habit, distribution and medicinal uses are given. Additionally, information from the literature on medicinal uses, chemical constituents and pharmacological effects are also provided.

The chemistry and biological significance of saponins in foods and feedingstuffs

Saponins occur widely in plant species and exhibit a range of biological properties, both beneficial and deleterious. This review, which covers the literature to mid 1986, is concerned with their occurrence in plants and their effects when consumed by animals and man. After a short discussion on the nature, occurrence, and biosynthesis of saponins, during which the distinction between steroidal and triterpenoid saponins is made, the structures of saponins which have been identified in a variety of plants used as human foods, animal feedingstuffs, herbs, and flavorings are described. Many of these compounds have been characterized only during the last 2 decades, and modern techniques of isolation, purification, and structural elucidation are discussed. Particular consideration is given to mild chemical and enzymatic methods of hydrolysis and to recent developments in the application of NMR and soft ionization MS techniques to structural elucidation. Methods currently used for the quantitative analysis of saponins, sapogenols, and glycoalkaloids are critically considered; advances in the use of newer methods being emphasized. The levels of saponins in a variety of foods and food plants are discussed in the context of the methods used and factors affecting these levels, including genetic origin, agronomic, and processing variables, are indicated. Critical consideration is given to the biological effects of saponins in food which are very varied and dependent upon both the amount and chemical structure of the individual compounds. The properties considered include membranolytic effects, toxic and fungitoxic effects, adverse effects on animal growth and performance, and the important hypocholesterolemic effect. A final section deals briefly with the pharmacological effects of saponins from ginseng, since use of this plant is increasing in certain sections of western society as well as being traditional in the Orient.