Anti-allergic triterpenes isolated from olive milled waste

The peels of sacred Lotus (Nelumbo nucifera) rhizomes suppress allergic reactions by inhibiting the A23187-induced degranulation in rat basophilic leukemia (RBL2H3) cells

We isolated ten compounds from methanolic extract of the peels of sacred lotus (Nelumbo nucifera) rhizomes which were identified as β-sitosterol linoleate 1, β-sitosterol 2, lupeol 3, stigmasterol 3-O-β-D-glucoside 4, oleanolic acid 5, betulinic acid 6, pinoresinol 7, 4-hydroxybenzoic acid 8, catechin 9 and gallocatechin 10. All of the isolated compounds from the peels of sacred lotus rhizomes are reported for the first time, and were investigated for their anti-allergic activity. We found that three of them, stigmasterol 3-O-β-D-glucoside 4, oleanolic acid 5 and pinoresinol 7, were capable of inhibiting A23187-induced degranulation in RBL-2H3 cells with IC50 values 0.18 ± 0.01 mM, 0.28 ± 0.06 mM, and 0.27 ± 0.01 mM, respectively. With an exception to 4, compounds 5 and 7 achieved the anti-allergic effect without affecting the cells viability even at higher concentrations with their selectivity indices (SI) being >5. By reducing A23187-induced degranulation, it is suggestive of a mechanism attenuation of Ca2+ elevation. Our findings suggest that, the peels of sacred lotus rhizomes would be beneficial for providing an inexpensive source for the production of bioactive compounds with anti-allergic effect.

Oleuropein Prevents OVA-Induced Food Allergy in Mice by Enhancing the Intestinal Epithelial Barrier and Remodeling the Intestinal Flora

SCOPE

This study assesses whether oleuropein prevents ovalbumin (OVA)-induced food allergy (FA) and investigates the underlying mechanisms.

METHODS AND RESULTS

A Balb/c FA mouse model is established and maintained for 7 weeks. The subjects are administered OVA by oral gavage to induce FA and supplemented with different oleuropein doses (1.00-20.00 mg kg^-1 per day) to evaluate its preventative efficacy. The results indicate that oleuropein effectively alleviates OVA-induced allergy symptoms and promotes temperature elevation in sensitized mice. The secretion of serology-specific OVA-immunoglobulin (Ig)E, OVA-IgG, and histamine is inhibited in the sensitized mice. Oleuropein dramatically upregulates the expression of intestinal tight junction (TJ) proteins, regenerating gene (Reg) IIIγ, and interleukin (IL)-22, enhancing the physical and biochemical barrier function of the intestinal epithelium. Additionally, oleuropein improves the immune homeostasis of the intestinal epithelium by affecting the function of mucosal mast cells and regulatory T (Treg) cells. The disordered intestinal flora of the sensitized mice also improves after oleuropein administration.

CONCLUSIONS

These findings suggest that oleuropein prevents FA by enhancing intestinal epithelial barrier function and improving immune homeostasis and intestinal flora in sensitized mice. Therefore, diets rich in oleuropein should be recommended for people with FA.

A cytotoxic triterpenoid from a Periplaneta americana-derived, Gordonia hongkongensis WA12-1-1

The secondary metabolites produced by microorganisms are a source of novel compounds with antitumor activities. In this study, we isolated biologically active secondary metabolites produced by microorganisms in the intestinal tract of Periplaneta americana. Based on the 16S rRNA gene sequencing, Gordonia hongkongensis WA12-1-1 was identified as the main microorganisms in the intestinal tract of P. americana. The obtained sequence was deposited in the National Center for Biotechnology Information (NCBI) database under the accession number MZ348554. The isolated secondary metabolites were separated and purified by thin layer chromatography, silica gel column chromatography, Sephadex column chromatography, open octadecyl silane column chromatography, high-performance liquid chromatography (HPLC), and semipreparative HPLC. Next, the structure of individual compounds was determined by ultraviolet spectroscopy, nuclear magnetic resonance, and mass spectrometry. A total of 20 compounds were isolated from the secondary metabolites produced by G. hongkongensis WA12-1-1. A total of 12 compounds were obtained from the crude ethyl acetate extract of the culture supernatant and eight from the cellular fraction. Compound 1 was identified as a triterpenoid named gordonterpene and showed cytotoxicity against A549 and HepG2 cell lines. These findings form a basis for further studies on the bioactivity of gordonterpene to tumor cells.

Neuroprotective effects of Olea europaea L. fruit extract against cigarette smoke-induced depressive-like behaviors in Sprague-Dawley rats

Depression is broadly acclaimed as a mental health anomaly and despite advancements in the development of antidepressant drugs, they are linked with side effects. Dietary modifications and medicinal plants like olives can be used as effective strategies due to their antioxidant, immune-modulatory, antiinflammatory, and anticonvulsant properties. Considering the compositional alterations in olive fruits during ripening, the antidepressant potential of olive fruits at different degrees of ripeness, that is, un-ripened (green) and ripened (black) was investigated. Rats were randomly divided into five groups: G₀ (Normal diet), G₁ (Normal diet + smoke exposure (SE), G₂ (Normal diet + SE + Citalopram), G₃ (Normal diet + SE + Green olive extract), and G₄ (Normal diet + SE + Black olive extract). Depressive-like behaviors were induced in all groups through cigarette smoke exposure except G₀ . Green and black olive extracts prevented depressive behaviors by reducing the immobility time of rats in forced swim test and tail suspension test while increased the latency to respond in hot plate assay. Moreover, lipid peroxidation in brain tissue was reduced with citalopram, green, and black olive extracts. Additionally, treatments also enhanced the antioxidant pool of brain tissues. Histological examination revealed that olive extracts and citalopram prevented cigarette smoke-induced moderate to severe necrosis and congestion in the brain parenchyma and elucidated antidepressant potential by improving the expression of monoamine oxidase-A, solute carrier family 6 member 4, and brain-derived neurotrophic factor genes. Conclusively, olives may act as a promising antidepressant agent in ameliorating cigarette smoke-induced depressive-like behaviors. PRACTICAL APPLICATIONS: Olive extracts at both ripening stages revealed an antidepressant-like effect almost similar to the standard antidepressant drug and also prevented oxidative damages. Therefore, from the current findings, it can be recommended that food ingredients with antidepressant potential like olives should be incorporated in future interventions to combat depression/psychiatric anomalies and diet therapy should be encouraged to alleviate lifestyle-related disorders.

Structurally diverse triterpenes obtained from the fruits of Ziziphus jujuba Mill. as inflammation inhibitors by NF-κB signaling pathway

Twenty-nine triterpenes were obtained from the fruits of Ziziphus jujuba Mill. through various chromatography methods, and their stereo-structures were confirmed by spectroscopic methods. Among them, 2α,3β,20-trihydroxylupane-28-oic acid (1) was identified as a new compound, and the ¹H and ¹³C NMR data of 7, 8 and 23, as well as the ¹³C NMR data of 17 are reported here for the first time. Meanwhile, the nitric oxide (NO) inhibitory activities of all compounds were examined in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. As results, compounds 2, 7, 10-13, 15, 16, 18-21, 26-29 were found to play important roles in suppressing NO production at 5 μM. The structure-activity relationships (SARs) on NO inhibition indicated that the ursolic and oleanolic acid skeletons, p-coumaroyl group substitution, six-membered A ring, and deoxygenation (loss of C[double bond, length as m-dash]O) in the C ring showed a more positive effect on the NO inhibitory activity of triterpenes, while the reduction of the A ring C[double bond, length as m-dash]O to OH was a negative factor. Moreover, it was found that compounds 15 and 19 could suppress the phosphorylation of IκBα and NF-κB/p65 to prevent it from shifting into the nucleus and downregulate the expression of inflammatory factors, such as iNOS, IL-6 and TNF-α. Our investigations revealed that the NO inhibitory effects of the active triterpenes obtained from Z. jujuba were mediated, at least in part, through the NF-κB signaling pathway.

Nine new dichapetalin-type triterpenoids from the twigs of Dichapetalum gelonioides (Roxb.) Engl

Nine previously undescribed dichapetalin-type triterpenoids (1-9), along with 12 reported compounds (10-21), were isolated from the twigs of Dichapetalum gelonioides. Their chemical structures were mainly elucidated by comprehensive analysis of HRMS, 1D and 2D NMR spectroscopic data. The absolute configuration of compound 1 was further determined based on single-crystal X-ray diffraction. In addition, a part of compounds were evaluated the effects of inhibitory NO production in LPS-induced RAW264.7 macrophages.

Related Pentacyclic Triterpenes Have Immunomodulatory Activity in Chronic Experimental Visceral Leishmaniasis

Leishmaniasis is a neglected tropical disease caused by the flagellated protozoa of the genus Leishmania that affects millions of people around the world. Drugs employed in the treatment of leishmaniasis have limited efficacy and induce local and systemic side effects to the patients. Natural products are an interesting alternative to treat leishmaniasis, because some purified molecules are selective toward parasites and not to the host cells. Thus, the aim of the present study was to compare the in vitro antileishmanial activity of the triterpenes betulin (Be), lupeol (Lu), and ursolic acid (UA); analyze the physiology and morphology of affected organelles; analyze the toxicity of selected triterpenes in golden hamsters; and study the therapeutic activity of triterpenes in hamsters infected with L. (L.) infantum as well as the cellular immunity induced by studied molecules. The triterpenes Lu and UA were active on promastigote (IC₅₀ = 4.0 ± 0.3 and 8.0 ± 0.2 μM, respectively) and amastigote forms (IC₅₀ = 17.5 ± 0.4 and 3.0 ± 0.2 μM, respectively) of L. (L.) infantum, and their selectivity indexes (SI) toward amastigote forms were higher (≥13.4 and 14, respectively) than SI of miltefosine (2.7). L. (L.) infantum promastigotes treated with Lu and UA showed cytoplasmic degradation, and in some of these areas, cell debris were identified, resembling autophagic vacuoles, and parasite mitochondria were swelled, fragmented, and displayed membrane potential altered over time. Parasite cell membrane was not affected by studied triterpenes. Studies of toxicity in golden hamster showed that Lu did not alter blood biochemical parameters associated with liver and kidney functions; however, a slight increase of aspartate aminotransferase level in animals treated with 2.5 mg/kg of UA was detected. Lu and UA triterpenes eliminated amastigote forms in the spleen (87.5 and 95.9% of reduction, respectively) and liver of infected hamster (95.9 and 99.7% of reduction, respectively); and UA showed similar activity at eliminating amastigote forms in the spleen and liver than amphotericin B (99.2 and 99.8% of reduction). The therapeutic activity of both triterpenes was associated with the elevation of IFN-γ and/or iNOS expression in infected treated animals. This is the first comparative work showing the in vitro activity, toxicity, and therapeutic activity of Lu and UA in the chronic model of visceral leishmaniasis caused by L. (L.) infantum; additionally, both triterpenes activated cellular immune response in the hamster model of visceral leishmaniasis.

Plant Secondary Metabolites: An Opportunity for Circular Economy

Moving toward a more sustainable development, a pivotal role is played by circular economy and a smarter waste management. Industrial wastes from plants offer a wide spectrum of possibilities for their valorization, still being enriched in high added-value molecules, such as secondary metabolites (SMs). The current review provides an overview of the most common SM classes (chemical structures, classification, biological activities) present in different plant waste/by-products and their potential use in various fields. A bibliographic survey was carried out, taking into account 99 research articles (from 2006 to 2020), summarizing all the information about waste type, its plant source, industrial sector of provenience, contained SMs, reported bioactivities, and proposals for its valorization. This survey highlighted that a great deal of the current publications are focused on the exploitation of plant wastes in human healthcare and food (including cosmetic, pharmaceutical, nutraceutical and food additives). However, as summarized in this review, plant SMs also possess an enormous potential for further uses. Accordingly, an increasing number of investigations on neglected plant matrices and their use in areas such as veterinary science or agriculture are expected, considering also the need to implement "greener" practices in the latter sector.

Common garlic (Allium sativum L.) has potent Anti-Bacillus anthracis activity

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrointestinal anthrax, a disease caused by Bacillus anthracis, remains an important but relatively neglected endemic disease of animals and humans in remote areas of the Indian subcontinent and some parts of Africa. Its initial symptoms include diarrhea and stomachache. In the current study, several common plants indicated for diarrhea, dysentery, stomachache or as stomachic as per traditional knowledge in the Indian subcontinent, i.e., Aegle marmelos (L.) Correa (Bael), Allium cepa L. (Onion), Allium sativum L. (Garlic), Azadirachta indica A. Juss. (Neem), Berberis asiatica Roxb. ex DC. (Daruharidra), Coriandrum sativum L. (Coriander), Curcuma longa L. (Turmeric), Cynodon dactylon (L.) Pers. (Bermuda grass), Mangifera indica L. (Mango), Morus indica L. (Black mulberry), Ocimum tenuiflorum L. (Ocimum sanctum L., Holy Basil), Ocimum gratissimum L. (Ram Tulsi), Psidium guajava L. (Guava), Zingiber officinale Roscoe (Ginger), were evaluated for their anti-Bacillus anthracis property. The usage of Azadirachta indica A. Juss. and Curcuma longa L. by Santals (India), and Allium sp. by biblical people to alleviate anthrax-like symptoms is well documented, but the usage of other plants is traditionally only indicated for different gastrointestinal disturbances/conditions.

AIM OF THE STUDY

Evaluate the above listed commonly available edible plants from the Indian subcontinent that are used in the traditional medicine to treat gastrointestinal diseases including those also indicated for anthrax-like symptoms for the presence of potent anti-B. anthracis activity in a form amenable to use by the general population in the endemic areas.

MATERIALS AND METHODS

Aqueous extracts made from fourteen plants indicated above were screened for their anti-B. anthracis activity using agar-well diffusion assay (AWDA) and broth microdilution methods. The Aqueous Garlic Extract (AGE) that displayed most potent anti-B. anthracis activity was assessed for its thermostability, stability under pH extremes encountered in the gastrointestinal tract, and potential antagonistic interaction with bile salts as well as the FDA-approved antibiotics used for anthrax control. The bioactive fractions from the AGE were isolated by TLC coupled bioautography followed by their characterization using GC-MS.

RESULTS

Garlic (Allium sativum L.) extract was identified as the most promising candidate with bactericidal activity against B. anthracis. It consistently inhibited the growth of B. anthracis in AWDA and decreased the viable colony-forming unit counts in liquid-broth cultures by 6-logs within 6-12 h. The AGE displayed acceptable thermostability (>80% anti-B. anthracis activity retained on incubation at 50 °C for 12 h) and stability in gastric pH range (2-8). It did not antagonize the activity of FDA-approved antibiotics used for anthrax control. GC-MS analysis of the TLC separated bioactive fractions of AGE indicated the presence of previously unreported constituents such as phthalic acid derivatives, acid esters, phenyl group-containing compounds, steroids etc. CONCLUSION: The Aqueous Garlic Extract (AGE) displayed potent anti-B. anthracis activity. It was better than that displayed by Azadirachta indica A. Juss. (Neem) and Mangifera indica L., while Curcuma longa L. (Turmeric) did not show any activity under the assay conditions used. Further work should be undertaken to explore the possible application of AGE in preventing anthrax incidences in endemic areas.

Secondary metabolites from Isodon ternifolius (D. Don) Kudo and their anticancer activity as DNA topoisomerase IB and Tyrosyl-DNA phosphodiesterase 1 inhibitors

Based on DNA topoisomerase IB (TOP1) and tyrosyl-DNA phosphodiesterase 1 (TDP1) inhibition of the ethanol extract of the roots of Isodon ternifolius (D. Don) Kudo (Labiatae), its secondary metabolites has been studied. Two new compounds, an ent-abietane diterpenoid isodopene A (1) and a 2,3-seco-triterpene isodopene B (13), along with 25 known compounds were isolated. Their structures were elucidated by spectroscopic analysis and theoretical calculations. The enzyme-based assays indicated that 1 and 13 showed strong (+++) and moderate (++) TOP1 inhibition, respectively. Two chalcone derivatives 11 and 12 were firstly found as dual TDP1 and TOP1 natural inhibitors, and showed synergistic effect with the clinical TOP1 inhibitors topotecan in MCF-7 cells. Compounds 8, 16, and 22 acted as TOP1 catalytic inhibitors with equipotent TOP1 inhibition to camptothecin (++++). Compounds 7 and 8 exhibited significant cytotoxicity against MCF-7, A549, and HCT116 cells with GI₅₀ values in the range of 2.2-4.8 μM. This work would provide valuable information that secondary metabolites from I. ternifolius could be developed as anticancer agents.

Melanogenesis Inhibitors from the Endophytic Fungus Aspergillus amstelodami

Two new compounds, named 3,4-dimethoxyphenyl α-d-ribofuranoside (1) and 3β-(β-d-glucopyranosyloxy)olean-12-ene-23,28,30-trioic acid (2), together with thirteen known compounds, were isolated from the white beans culture of the marine derived endophytic fungus Aspergillus amstelodami. Structure elucidation of the new compounds was carried out by one-, two-dimensional spectroscopy, and high resolution electrospray ionization mass. The antimelanogenic and anti-allergic activity of the isolated compounds were investigated. Compounds 4, 7, 1, 3, 11, 6 and 9 selectively suppressed melanin production in B16 melanoma cells, using arbutin as a positive control. Their IC₅₀ values were 30.8±5.57, 38.5±6.08, 52.6±6.64, 98.0±1.16, 100.4±3.05, 112.0±0.22 and 144.7±2.35 μm, respectively, while that of arbutin was 151.7±1.27 μm. The tested compounds did not show any significant anti-allergic activity in RBL-2H3 cells, as compared to quercetin.

Anti-allergic effects of the ethanol extract of Syzygium formosum (Wall.) Masam leaves and its immunoregulatory mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

As documented in a Vietnamese traditional medical encyclopedia, Syzygium formosum (Wall.) Masam leaves have been routinely used among indigenous Vietnamese people for treatment of various allergy-like symptoms including dermatitis and rhinitis.

AIM OF THE STUDY

Anti-allergic activity of S. formosum leaves was examined with a mouse model of chicken ovalbumin (cOVA)-induced food allergy, and mechanisms underlying the anti-allergic effect were explored.

MATERIAL AND METHODS

BALB/c mice were administered i.p. cOVA (20μg) plus alum (2mg) twice on day 0 and 14 for sensitization (immunization). Two weeks after the second immunization, the mice were administered cOVA (50mg) p.o. 5 times every 3 days to induce food allergy symptoms (i.e., anaphylaxis, diarrhea, and drop in the body temperature). Ethanol extract of dried leaves of S. formosum (80mg/kg or 200mg/kg body weight) was administered p.o. daily during the induction (challenge) period.

RESULTS

Treatment with the S. formosum leaves ethanol extract ameliorated the allergic symptoms to a significant extent and in a dose-dependent manner. The treatment also resulted in a significant improvement in the inflammatory lesion in the small intestine and reduction in the numbers of mast cells and eosinophils recruited to the lesion. The treatment also brought about a significant reduction in the levels of Th2 cytokines produced by the mesenteric lymph node cells cultured ex vivo with cOVA. The passive anaphylaxis experiment also showed that the extract treatment impaired the mast cell function.

CONCLUSION

Our study provides a scientific basis for the traditional (indigenous) use of the S. formosum leaves extract for the treatment of various allergy symptoms in Vietnam. In addition, the results show that the extract has activities to suppress antigen-specific Th2 T cell immune responses and the mast cell function, which are directly related with its anti-allergic effect.