Piptadenin, a Novel 3,4-Secooleanane Triterpene and Piptadenamide, a New Ceramide from the Stem Bark of Piptadeniastrum africanum (Hook.f.) Brenan

Diverse Triterpenoids from Mastic Produced by Pistacia lentiscus and Their Anti-Inflammatory Activities

Eight undescribed triterpenoids (1-8), including one apotirucallane-type triterpenoid (1), six tirucallane-type triterpenoids (2-7), and one oleanane-type triterpenoid (8), along with ten known compounds (9-18) were isolated from the resins of Pistacia lentiscus. Their structures were elucidated by integrating NMR spectroscopic analyses and ESI-HR-MS. Compounds 5, 11-17 exhibited moderate inhibitory abilities against NO production in LPS-induced RAW264.7 cells, with IC₅₀ values in the range of 18.26-50.37 μM, compared to that of the positive control dexamethasone (IC₅₀ =20.24 μM).

Isolation and characterization of chemical constituents from Chaerophyllum bulbosum roots and their enzyme inhibitory and antioxidant effects

Isolation and bioactive effects of the roots of Chaerophyllum bulbosum L. were firstly investigated herein. Enzyme (acetylcholinesterase, butyrylcholinesterase, urease, α-amylase, α-glucosidase, and tyrosinase) inhibitory effects of C. bulbosum root extracts were tested. Three known compounds, n-heptadecanyl eicosanoate (1), stigmasterol (2), and β-sitosterol-3-O-β-d-glucopyranoside (3) were isolated from C. bulbosum. Antioxidant and enzyme inhibitory effects of isolated compounds were investigated. The hexane extract (IC₅₀: 349.58 ± 0.06 μg/mL) displayed a higher α-glucosidase inhibitory effect than the standard (IC₅₀: 378.66 ± 0.14 μg/mL). The best inhibitory effect was found in compound 2 on AChE (46.40 ± 0.31%), BChE (56.41 ± 0.54%), and urease (92.47 ± 0.11%); compound 1 on α-amylase (22.27 ± 0.61%); and compound 3 on α-glucosidase (12.43 ± 0.25%) and tyrosinase (19.00 ± 0.16%). All isolated compounds showed moderate antioxidant effects in all assays. This study contributes to the therapeutic uses of Chaerophyllum roots and emphasizes the value of C. bulbosum species for the development of novel therapeutic agents.

Antinociceptive Activity of Compounds from the Aqueous Extract of Melampodium divaricatum

A decoction prepared from the aerial parts of Melampodium divaricatum showed antinociceptive and antihyperalgesic responses when tested in the formalin model in mice. From the CH₂ Cl₂ fraction of the decoction, two non-previously reported secondary metabolites, 3-O-β-D-glucopyranosyl-16α-hydroxy-ent-kaurane (1) and melampodiamide (2) [(2'R*,4'Z)-2'-hydroxy-N-[(2S*,3S*,4R*)-1,3,4-trihydroxyoctadec-2-yl]tetracos-4-enamide] were separated and characterized by spectroscopic, spectrometric, and computational techniques. The flavonoids isoquercitrin and hyperoside, which possessed noted antinociceptive properties, were obtained from the active AcOEt fraction of the decoction. The chemical composition of the essential oil of the plant was also analyzed by gas chromatography-mass spectrometry. The major constituents were (E)-caryophyllene, germacrene D, β-elemene, δ-elemene, γ-patchoulene, and 7-epi-α-selinene. Headspace solid-phase microextraction analysis detected (E)-caryophyllene as the main volatile compound of the plant.

Compound isolation and biological activities of Piptadeniastrum africanum (hook.f.) Brennan roots

ETHNOPHARMACOLOGICAL RELEVANCE

The dicotyledonous plant Piptadeniastrum africanum (hook.f.) Brennan (Fabaceae) is used in traditional medicine to treat various human complaints including bronchitis, coughing, urino-genital ailments, meningitis, abdominal pain, treatment of wounds, malaria and gastrointestinal ailments, and is used as a purgative and worm expeller.

AIM OF THE STUDY

The present study describes the phytochemical investigation and the determination of the antimicrobial, antiplasmodial and antitrypanosomal activities of crude extract, fractions and compounds extracted from Piptadeniastrum africanum roots.

MATERIALS AND METHODS

Isolated compounds were obtained using several chromatographic techniques. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR) and by comparing their NMR data with those found in literature. In vitro antimicrobial activity of samples was evaluated using the microdilution method on bacterial (Escherichia coli, Proteus mirabilis, Staphylococcus aureus) and fungal (Candida krusei) strains, while in vitro cell-growth inhibition activities were assessed against two parasites (Trypanosoma brucei brucei and Plasmodium falciparum strain 3D7). The cytotoxicity properties of samples were assayed against HeLa human cervical carcinoma.

RESULTS

Five compounds were isolated and identified as: tricosanol 1, 5α-stigmasta-7,22-dien-3-β-ol 2, betulinic acid 3, oleanolic acid 4 and piptadenamide 5. This is the first report of the isolation of these five compounds from the roots of P. africanum. The (Hex:EtOAc 50:50) fraction exhibited moderate antibacterial activity against P. mirabilis (MIC 250 μg/mL), while the other fractions and isolated compounds had weak antimicrobial activities. Only the EtOAc fraction presented a moderate antimalarial activity with an IC₅₀ of 16.5 μg/mL. The MeOH crude extract and three fractions (Hexane, Hexane-EtOAc 25% and EtOAc-MeOH 25%) exhibited significant trypanocidal activity with IC₅₀ values of 3.0, 37.5, 3.8 and 9.5 μg/mL, respectively.

CONCLUSION

These results demonstrated a scientific rational of the traditional uses of P. africanum and indicate that this plant should be further investigated to identify some of the chemical components that exhibited the activities reported in this study and therefore may constitute new lead candidates in parasiticidal drug discovery.

Evaluation of Pharmacological and Phytochemical Profiles Piptadeniastrum africanum (Hook.f.) Brenan Stem Bark Extracts

The stem bark (SB) of Piptadeniastrum africanum (PA) has been extensively used in African traditional medicinal systems. However, there is a dearth of scientific information regarding its possible activity in the management of type II diabetes, Alzheimer’s disease, and skin hyperpigmentation disorders. This study therefore attempted to elucidate the in vitro inhibitory action of ethyl acetate, methanol, and water extracts of P. africanum stem bark (PA-SB) on α-amylase, α-glucosidase, acetylcholinesterase, butyrylcholinesterase, and tyrosinase. Cell viability, catecholamine, and 3-hydroxykynurenine levels of hypothalamic HypoE22 cells exposed to PA-SB extracts were also investigated. The phytochemical profiles of the extracts were determined by high performance liquid chromatography (HPLC) and antioxidant properties were investigated. Saponin (867.42 mg quillaja equivalent/g) and tannin (33.81 mg catechin equivalent/g) contents were higher in the methanol extract. Multiple dihydroxy-trimethoxy(iso)flavone isomers, loliolide, eriodictyol, naringenin, luteolin, chrysoeriol, apigenin, and liquiritigenin, were characterized from PA-SB extracts using HPLC. The methanol extract of PA-SB showed highest inhibitory activity against acetylcholinesterase (4.88 mg galantamine equivalent (GALAE)/g extract), butyrylcholinesterase (5.37 mg GALAE/g extract), and tyrosinase (154.86 mg kojic acid equivalent/g extract) while α-glucosidase was effectively inhibited by the ethyl acetate extract (15.22 mmol acarbose equivalent/g extract). The methanol extract of PA-SB also showed potent antioxidant properties (493.87, 818.12, 953.07, and 732.19 mg Trolox equivalent/g extract, for 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), cupric reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP) assays, respectively). PA-SB extracts exhibited antioxidant activity and promising inhibition against key enzymes related to type II diabetes, Alzheimer’s disease, and skin hyperpigmentation disorders. Additionally, all extracts were able to contrast hydrogen peroxide-induced oxidative stress, in HypoE22 cells, thus restoring basal catecholamine and 3-hydroxykinurenine levels, whereas only methanol and water extracts stimulated basal dopamine release. Overall, data from the present study contribute to the biological assessment of P. africanum that appears to be a promising source of natural compounds with protective and neuromodulatory effects.

Bio-efficacy of medicinal plants used for the management of diabetes mellitus in Gabon: An ethnopharmacological approach

BACKGROUND/AIM

People suffering of diabetes increased significantly worldwide. Population, in Sub-Saharan Africa and mainly in Gabon, rely on medicinal plants to manage diabetes, as well in rural as in urban areas. This study aimed to survey a wide range of Gabonese plants for their antidiabetic activity.

MATERIALS AND METHODS

This study focused on the identification of medicinal plants used in the local treatment of diabetes mellitus. Ethnobotanical investigations were carried out in rural and urban areas of three provinces of Gabon using a semi-structured interview.

RESULTS

About 50 plant species belonging to 31 families and 50 genera were recorded, a majority of which have been documented previously to have medicinal properties. Most have documented antidiabetic properties with characterized therapeutic chemical compounds. Of the plant parts used for treatment, stem barks were employed most frequently (50%), followed by leaves (26%); the remaining 24% comprised roots, fibers, fruit, bulbs, flowers, rhizom, skin, and stem. Regarding the mode of preparation, decoction was the most widely used (58%), followed by maceration (18%) and infusion (14%). Almost all the plant products were administered orally (98%).

CONCLUSIONS

Taken in concert, this study highlights the possibility of exploiting traditional knowledge of specific medicinal plants for the inexpensive treatment and management of diabetes.

Anti-arthritic property of crude extracts of Piptadeniastrum africanum (Mimosaceae) in complete Freund's adjuvant-induced arthritis in rats

BACKGROUND

Rheumatoid arthritis, disease of unknown causes is a rheumatic and autoimmune pathology, recognised for its increasing frequency and its adverse consequences. It is a disease that occurs in most cases between 50 and 60 years and women are more affected than men. This study aimed at evaluating immunomodulatory and anti-arthritis capacity of aqueous and methanol extracts of stem bark of Piptadeniastrum africanum (Mimosaceae).

METHODS

ROS production from phagocytes, proliferation of T-cells, TNF-α and IL-1β production and cytotoxicity were performed by using chemiluminescence technique, liquid scintillation counter, ELISA and MTT assay, respectively. Anti-arthritic activity was evaluated using a model of adjuvant induced arthritis.

RESULTS

Methanol and aqueous extracts of Piptadeniastrum africanum significantly (P < 0.001) inhibited extracellular and intracellular ROS production. These extracts also possess significant (P < 0.001) inhibitory activity on T-cell proliferation other than reduced TNF-α and IL-1β production. Piptadeniastrum africanum also significantly exhibited antiarthritic activity in complete Freund's adjuvant induced arthritis in rat associated with a significant anti-inflammatory and anti-hyperalgesia activity.

CONCLUSIONS

Immunomodulatory, anti-inflammatory, antihyperalgesia and anti-arthritis potential revealed in this study approve that, Piptadeniastrum africanum is a plant rich in compounds with anti-arthritic properties.