Bioactive Phytochemicals with Anti-Aging and Lifespan Extending Potentials in Caenorhabditis elegans.

In the forms of either herbs or functional foods, plants and their products have attracted medicinal, culinary, and nutraceutical applications due to their abundance in bioactive phytochemicals. Human beings and other animals have employed those bioactive phytochemicals to improve health quality based on their broad potentials as antioxidant, anti-microbial, anti-carcinogenic, anti-inflammatory, neuroprotective, and anti-aging effects, amongst others. For the past decade and half, efforts to discover bioactive phytochemicals both in pure and crude forms have been intensified using the Caenorhabditis elegans aging model, in which various metabolic pathways in humans are highly conserved. In this review, we summarized the aging and longevity pathways that are common to C. elegans and humans and collated some of the bioactive phytochemicals with health benefits and lifespan extending effects that have been studied in C. elegans. This simple animal model is not only a perfect system for discovering bioactive compounds but is also a research shortcut for elucidating the amelioration mechanisms of aging risk factors and associated diseases.

3-O-Methyl-Alkylgallates Inhibit Fatty Acid Desaturation in Mycobacterium tuberculosis.

In the quest for new antibacterial lead structures, activity screening against Mycobacterium tuberculosis identified antitubercular effects of gallic acid derivatives isolated from the Nigerian mistletoe Loranthus micranthus Structure-activity relationship studies indicated that 3-O-methyl-alkylgallates comprising aliphatic ester chains with four to eight carbon atoms showed the strongest growth inhibition in vitro against M. tuberculosis, with a MIC of 6.25 µM. Furthermore, the most active compounds (3-O-methyl-butyl-, 3-O-methyl-hexylgallate, and 3-O-methyl-octylgallate) were devoid of cytotoxicity against various human cell lines. Furthermore, 3-O-methyl-butylgallate showed favorable absorption, distribution, metabolism, and excretion (ADME) criteria, with a Papp of 6.2 × 10-6 cm/s, and it did not inhibit P-glycoprotein (P-gp), CYP1A2, CYP2B6 or CYP3A4. Whole-genome sequencing of spontaneous resistant mutants indicated that the compounds target the stearoyl-coenzyme A (stearoyl-CoA) delta-9 desaturase DesA3 and thereby inhibit oleic acid synthesis. Supplementation assays demonstrated that oleic acid addition to the culture medium antagonizes the inhibitory properties of gallic acid derivatives and that sodium salts of saturated palmitic and stearic acid did not show compensatory effects. The moderate bactericidal effect of 3-O-methyl-butylgallate in monotreatment was synergistically enhanced in combination treatment with isoniazid, leading to sterilization in liquid culture.

Ganoderma lucidum methyl ganoderate E extends lifespan and modulates aging-related indicators in Caenorhabditis elegans.

Methyl Ganoderate E (MGE) is a triterpenoid derived from Ganoderma lucidum (Reishi), an edible mushroom, commonly processed into food forms such as soups, drinks, culinary dishes, and supplements. MGE has been shown to inhibit 3T3-L1 murine adipocyte differentiation when combined with other G. lucidum triterpenes. However, the specific effect of MGE on biological processes remains unknown. In this study, we present the first evidence of MGE's anti-aging effect in Caenorhabditis elegans. Through our screening process using the UPRER regulation ability, we evaluated a library of 74 pure compounds isolated from G. lucidum, and MGE exhibited the most promising results. Subsequent experiments demonstrated that MGE extended the lifespan by 26% at 10 µg ml-1 through daf-16, hsf-1, and skn-1-dependent pathways. MGE also enhanced resistance to various molecular stressors, improved healthspan, increased fertility, and reduced the aggregation of alpha-synuclein and amyloid-beta. Transcriptome data revealed that MGE promoted processes associated with proteolysis and neural activity, while not promoting cell death processes. Collectively, our findings suggest that G. lucidum MGE could be considered as a potential anti-aging intervention, adding to the growing list of such interventions.

Antimicrobial Effects of a Lipophilic Fraction and Kaurenoic Acid Isolated from the Root Bark Extracts of Annona senegalensis.

Root bark preparation of Annona senegalensis Pers. (Annonaceae) is used in Nigerian ethnomedicine for treatment of infectious diseases. Extraction of the A. senegalensis powdered root bark with methanol-methylene chloride (1 : 1) mixture yielded the methanol-methylene extract (MME) which was fractionated to obtain the ethyl acetate fraction (EF). The EF on further fractionation gave two active subfractions, F1 and F2. The F1 yielded a lipophilic oily liquid while F2 on purification, precipitated white crystalline compound, AS2. F1 was analyzed using GC-MS, while AS2 was characterized by proton NMR and X-ray crystallography. Antibacterial and antifungal studies were performed using agar-well-diffusion method with 0.5 McFarland standard and MICs calculated. GC-MS gave 6 major constituents: kaur-16-en-19-oic acid; 1-dodecanol; 1-naphthalenemethanol; 6,6-dimethyl-bicyclo[3.1.1]hept-2-ene-2-ethanol; 3,3-dimethyl-2-(3-methylbuta-1,3-dienyl)cyclohexane-1-methanol; 3-hydroxyandrostan-17-carboxylic acid. AS2 was found to be kaur-16-en-19-oic acid. The MICs of EF, F1, and AS2 against B. subtilis were 180, 60, and 30 µg/mL, respectively. AS2 exhibited activity against S. aureus with an MIC of 150 µg/mL, while F1 was active against P. aeruginosa with an MIC of 40 µg/mL. However, the extracts and AS2 exhibited no effects against Candida albicans and Aspergillus niger. Therefore, kaurenoic acid and the lipophilic fraction from A. senegalensis root bark exhibited potent antibacterial activity.

A novel sesquiterpene acid and an alkaloid from leaves of the Eastern Nigeria mistletoe, Loranthus micranthus with potent immunostimulatory activity on C57BL6 mice splenocytes and CD69 molecule.

CONTEXT: The Eastern Nigeria mistletoe, Loranthus micranthus Linn. (Loranthaceae), is used in the treatment of several diseases including immune-modifying diseases and thus there is a need to identify the immunoactive constituents. OBJECTIVE: This research isolated and characterized the immunoactive constituents in the Eastern Nigeria mistletoe. MATERIALS AND METHODS: Bioassay-guided fractionation was employed in the isolation and purification of the constituents. The characterized compounds were screened for immunostimulatory activities on isolated C57BL/6 mice splenocytes and early activation marker, CD69 at concentrations of 10, 25, and 100 µg/mL using flow cytometry techniques and compared to lipopolysaccharide (LPS; 10 µg/mL) and concanavalin A (ConA; 2 µg/mL) as standards. RESULTS: Two compounds, a novel sesquiterpene, 2, 3-dimethoxy-benzo [a, b] cyclopentenyl-3',3',5'-trimethyl pyran-4-carboxylic acid, and a known alkaloid, lupinine were isolated and characterized. The compounds (25 µg/mL) showed statistically significantly (p < 0.05) stimulatory activity on the splenocytes with values of 56.34 ± 0.26% and 69.84 ± 0.19%, respectively, compared to 7.58 ± 0.42% recorded for the unstimulated control. Similarly, the CD69 expression assay showed immunostimulation with statistically significant values (p < 0.05) of 2.31 ± 0.07% and 2.71 ± 0.03%, respectively, compared to 1.69 ± 0.05% recorded for the nonstimulated control. DISCUSSION: These data suggest that the isolated compounds possess immunomodifying abilities. In addition, the activation of the CD69 molecule is possibly one of its mechanisms of action. CONCLUSION: These compounds may be responsible in part, for the immunostimulatory activities already established for the Eastern Nigeria mistletoes.

Analysis of constituents of the eastern Nigeria mistletoe, Loranthus micranthus linn revealed presence of new classes of osteogenic compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Mistletoe extracts (decoctions) are used traditionally in eastern Nigeria for the management of bone pain, post menopausal syndrome and diabetes amongst several other ailments. While scientific evidence supporting its folkloric use as an antidiabetic agent has been documented, the age-long practice of its use in treatment of post menopausal syndrome has not been scientifically validated. Postmenopausal osteoporosis accounts for one of the prevalent disease conditions in aging population globally. This situation is exacerbated by the lack of osteogenic therapy. In search for plants of Nigerian origin with osteogenic potential, we evaluated eastern Nigerian mistletoe, having ethnotraditional claims of anti-diabetic, anti-hypertensive and anti-cancer activities as well as preventive effect in various post-menopausal syndromes. MATERIALS AND METHODS: Methanolic extracts of mistletoe leaves harvested from three host tress - Kola acuminata (KM), Citrus spp (CM) and Garcinia kola (GKM) - were evaluated for osteoblast viability and osteogenic activities using primary rat calvaria culture. Lupeol (1) was isolated from the stem bark of Bombax ciba and its congener, dihydoxylupeol palmitate (2) in addition to three other compounds; 3-methoxy quercetin (3), 3,4,5-trimethoxy gallate (4), and friedelin (5) were isolated from the leaves of mistletoes species. Following their chemical characterization, the compounds were evaluated for osteogenic potential using validated models including alkaline phosphatase (ALP) assay, mineralization assay and expression of osteogenic genes - bone morphogenetic protein-2 (BMP2) and osteoblast transcription factor (RUNX2) - in primary calvarial cultures harvested from neonatal rats. Uterine estrogenicity of the extracts was tested in adult female Sprague Dawley rats. RESULTS: Methanol extracts of mistletoe from three hosts exhibited increase in ALP activity (a marker of osteoblast differentiation) at lower concentrations (0.2-0.8 µg/ml) and either no or inhibitory effect at higher concentrations (1.6 and 3.2 µg/ml). None of the extract had cytotoxicity to osteoblasts at the concentrations tested. Five compounds viz. 1 from Bombax ciba, and 2-5 were isolated from the mistletoe leaves. Out of these, 5 exhibited significant loss of osteoblast viability and hence it was not considered further. All four compounds exhibited stimulatory effects on osteoblast differentiation as assessed by ALP assay and determination of osteogenic gene expression. Compound 2 was relatively more potent than its precursor, compound 1 in stimulating BMP2 upregulation. KM did not show uterine estrogenicity. CONCLUSION: Methanolic extracts from the three mistletoes species possess in vitro osteogenic activity, and from these extracts three new classes of compounds have been found to promote osteoblast differentiation in vitro. In light of these findings, we propose that mistletoe species may be developed as safer alternative(s) in the management of diseases where lack of bone formation is the pathology.

Anticonvulsant effect of kaurenoic acid isolated from the root bark of Annona senegalensis.

CONTEXT: The herbal preparations of Annona senegalensis Pers. (Annonaceae) root bark are used in Nigerian ethnomedicine for the treatment of epilepsy and febrile seizures. The scientific evidence for this effect has been reported. OBJECTIVE: The aim of this study was to identify and characterize the active constituent responsible for the anticonvulsant effect. MATERIALS AND METHODS: Bioactive-guided fractionation of the methanol-methylene chloride root bark extract (MME) of A. senegalensis using pentylenetetrazole (PTZ)-induced seizures in mice, afforded a potent anticonvulsant ethyl-acetate fraction (EF). Further fractionation of the EF yielded eight sub-fractions (F1-F8) which were tested for anticonvulsant activity. The sub-fraction F2 yielded white crystals that were purified to obtain A. senegalensis crystals, AS2. The AS2, which exhibited potent anticonvulsant effects, was characterized by 1D and 2D NMR spectroscopy, mass spectroscopy and X-ray crystallography. RESULTS: The AS2 was characterized as kaur-16-en-19-oic acid (KA), a diterpenoid. The AS2 indicated an oral LD50 of 3800 mg/kg. The results showed that the MME, EF and AS2 significantly (P<0.05) and dose-dependently delayed the onset of myoclonic spasms and tonic-clonic phases of seizures induced by PTZ and maximal electroshock seizures (MES). DISCUSSION AND CONCLUSION: Kaurenoic acid was identified as the anticonvulsant principle in the root bark extract of A. senegalensis. The anticonvulsant effect of the MME, EF and AS2 is most likely being mediated through central inhibitory mechanisms.

Three hydroxylated lupeol-based triterpenoid esters isolated from the Eastern Nigeria mistletoe parasitic on Kola acuminata.

Column fractionation and purification of an n-hexane fraction led to the isolation of three lupeol-based triterpenoid esters from the leaves of the Eastern Nigeria mistletoe, Loranthus micranthus Linn parasitic on a local kola nut tree, Kola acuminata. These three compounds were adequately characterised using a combination of UV/visible, IR, NMR (¹³C-NMR and ¹H-NMR), DEPT, MS and two-dimensional correlation (H-H COSY, Hetero-nuclear Single Quantum Correlation (HSQC), HMBC, NOE and NOESY) studies as 7ß,15α-dihydroxyl-lup-20(29)-ene-3ß-esters of palmitic (I), stearic (II) and eicosanoic acids (III). The characterisation of other isolated compounds is ongoing. Remarkably, this is the first report of the existence of fatty acid esters of an unusual 7ß,15α-dihydroxylated lupeol in the Eastern Nigeria mistletoe. These isolated compounds might contribute in part to the numerous established bio-activities of the Eastern Nigeria mistletoes.

Immunomodulatory activity of a lupane triterpenoid ester isolated from the eastern Nigeria mistletoe, Loranthus micranthus (Linn).

OBJECTIVE: To provide further evidence for the ethnomedicinal use of the Eastern Nigeria mistletoe, Loranthus micranthus (L. micranthus), as an immunostimulant. METHODS: Solvent fractions from the crude extract of the mistletoe plant was obtained and screened by the cell mediated delayed type hypersensitivity reaction (DTHR) model in mice. Then the immunomodulatory potentials of a major lupane triterpenoid ester isolated from an active hexane fraction of the Eastern Nigeria mistletoe was investigated. Three lupeol-based triterpenoid esters: 7ß 15α-dihydroxyl-lup-20(29)-ene-3ß-palmitate (I), 7ß, 15α-dihydroxyl-lup-20(29)-ene-3ß-stearate (II) and 7ß, 15α-dihydroxyl-lup-20(29)-ene-3ß-decadecanoate (III) were isolated from the plant leaves epiphyting on a local kola nut tree and were characterized. Compound 1 was subjected to cell proliferation studies using C57Bl/6 splenocytes at three dose levels (5, 25 and 100 µg/mL) in presence of controls. Furthermore, the effect of this compound on IL-8 receptor expression was evaluated at three doses (1, 5 and 10 µg/mL) using the real time polymerase chain reaction assay. RESULTS: This triterpenoid ester produced some enhancement of the splenocytes at the tested doses but at doses higher than 5 µg/mL caused inhibition of the IL-8 receptor expression. CONCLUSIONS: The present findings support the ethnomedicinal use of the Eastern Nigeria Mistletoe in the management of diseases affecting the immune system. The triterpenoid(s) have some immunomodulatory abilities on splenocytes and IL-8 receptors and may partly account for the overall immunomodulatory activity of this plant.

Comparative acute toxicities and immunomodulatory potentials of five Eastern Nigeria mistletoes.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditionally, mistletoes of Eastern Nigeria origin, Loranthus micranthus Linn. have been used as immunostimulant for the management of certain diseases with high profile immune depleting potentials. This practice has remained till date without scientific validation. AIM OF STUDY: To obtain and validate evidence for or against its continued use as immunostimulant and afford data for further studies on this specie of mistletoe. The present work is an in vivo proof of ethnopharmacological concept of the age long immunomodulatory use of our local mistletoe. MATERIALS AND METHODS: Aqueous-methanol extracts of the plant leaves from five different host trees were evaluated for immunomodulatory activity using four in vivo models in mice or rats, namely; total and differential leukocyte count (TLC and DLC), the cellular mediated delayed-type hypersensitivity reaction (DTHR) test, the humoral mediated antibody titration (AT) test and the cyclophosphamide-induced myelosuppression (CIM) test at different dose levels (100, 200 and 400 or 50, 100 and 250 mg kg(-1); depending on model) against standard controls. Phytochemical and acute toxicity tests were equally carried out on all the extracts. RESULTS: Results obtained indicate that all the mistletoes contained the same phytochemical constituents, although in varying amounts. The mistletoes exhibited statistically significantly different (p < 0.05 or p < 0.001, ANOVA) immunomodulatory (up-regulatory) activities in the overall order of that from Kola acuminata > Citrus spp > Persia americana > Parkia biglobosa > Pentaclatra macrophylla. LD(50) values were generally greater than 5000 mg/kg. CONCLUSION: The present study confirms the Eastern Nigeria mistletoe as a potent and safe alternative or complementary medicine for the management of immunodeficiency diseases.