Protective effect of Aframomum melegueta phenolics against CCl₄-induced rat hepatocytes damage; role of apoptosis and pro-inflammatory cytokines inhibition

Aframomum Melegueta: Evaluation of Chronic Toxicity, HPLC Profiling, and In Vitro/In Vivo Antioxidant Assessment of Seeds Extracts

Aframomum melegueta, commonly known as grains of paradise, is a medicinal plant celebrated for its rich phytochemical content and therapeutic properties. This study evaluated the antioxidant and cytotoxic potentials of its ethanolic and methanolic extracts, both in vitro and in vivo, while also analyzing their chemical profiles. HPLC analysis identified key compounds, including gallic acid, caffeic acid, caffeine, coumarin, rutin, catechin, ferulic acid, and quercetin. Chronic toxicity assessments confirmed the safety of the extracts, with no adverse effects on animal health, particularly in liver histopathology. Cytotoxicity results indicated reduced splenocyte viability at the highest concentrations. The extracts exhibited significant antioxidant activity in DPPH•, FRP, and phosphomolybdate assays, demonstrating their effectiveness as antiradical agents. In vivo antioxidant results showed a reduction in lipid peroxidation levels in serum and liver, highlighting the extracts' ability to mitigate oxidative stress. Additionally, the extracts provided protection against H2O2-induced erythrocyte hemolysis and modulated NO production in peritoneal macrophages. These findings underscore the therapeutic potential of A. melegueta extracts, suggesting their promise in developing preventive strategies for oxidative stress-related chronic diseases.

Antimicrobial and anti-virulence activities of 4-shogaol from grains of paradise against gram-negative bacteria: Integration of experimental and computational methods

ETHNOPHARMACOLOGICAL RELEVANCE

Bacterial resistance to antibiotics is a growing global concern, highlighting the urgent need for new antimicrobial candidates. Aframomum melegueta was traditionally used for combating urinary tract and soft tissue infections, which implies its potential as an antimicrobial agent.

AIM OF STUDY

This study was designed to explore the antibacterial and anti-virulence capabilities of 4-shogaol isolated from A. melegueta seeds versus gram-negative bacteria: Serratia marcescens, Klebsiella pneumoniae, Acinetobacter baumannii, and the clinically important pathogen Pseudomonas aeruginosa.

MATERIALS AND METHODS

4-Shogeol was isolated from A. melegueta seeds and its MICs were determined for Acinetobacter baumannii (ATCC-17978), Pseudomonas aeruginosa (ATCC-27853), Klebsiella pneumoniae (ATCC-700603), and Serratia marcescens clinical isolate. The anti-efflux activity and effect on the bacterial cell membrane for the compound were evaluated. Furthermore, the anti-virulence activities of the compound were evaluated. The effects of 4-shogeol at sub-MIC on bacterial motility, biofilm formation, and production of virulent enzymes and pigments were assessed. The anti-quorum sensing activities of 4-shogeol were evaluated virtually and by quantification its effect on the expression of quorum sensing encoding genes. The in vivo protection assay was conducted to evaluate the effect of 4-shogaol on the P. aeruginosa capacity to induce pathogenesis in mice. Finally, the effect of shogaol-antibiotics combination was assessed.

RESULTS

The research revealed that 4-shogaol's antibacterial action primarily involves disrupting the bacterial cell membrane and efflux pumps. It also exhibited significant anti-virulence effects by reducing biofilm development and repressing virulence factors production, effectively protecting mice against P. aeruginosa infection. Furthermore, when combined with antibiotics, 4-shogaol demonstrated synergistic effects, leading to reduced minimum inhibitory concentrations (MICs) against P. aeruginosa. Its anti-virulence properties were linked to its ability to disrupt bacterial quorum sensing (QS) mechanisms, as evidenced by its interaction with QS receptors and downregulation of QS-related genes. Notably, in silico analysis indicated that 4-shogaol exhibited strong binding affinity to different P. aeruginosa QS targets.

CONCLUSION

These findings suggest that 4-shogaol holds promise as an effective anti-virulence agent that can be utilized in combination with antibiotics for treating severe infections caused by gram-positive bacteria.

A Review on the Potential Species of the Zingiberaceae Family with Anti-viral Efficacy Towards Enveloped Viruses

Natural products are a great wellspring of biodiversity for finding novel antivirals, exposing new interactions between structure and operation and creating successful defensive or remedial methodologies against viral diseases. The members of Zingiberaceae traditional plant and herbal products have robust anti-viral action, and their findings will further lead to the production of derivatives and therapeutic. Additionally, it highlights the insight of utilizing these phytoextracts or their constituent compounds as an emergency prophylactic medicine during the pandemic or endemic situations for novel viruses. In this connection, this review investigates the potential candidates of the Zingiberaceae family, consisting of bioactive phytocompounds with proven antiviral efficacy against enveloped viruses. The present study was based on published antiviral efficacy of Curcuma longa, Zingiber officinale, Kaempferia parviflora, Aframomum melegueta Elettaria cardamomum, Alpina Sps (belongs to the Zingiberaceae family) towards the enveloped viruses. The relevant data was searched in Scopus”, “Scifinder”, “Springer”, “Pubmed”, “Google scholar” “Wiley”, “Web of Science”, “Cochrane “Library”, “Embase”, Dissertations, theses, books, and technical reports. Meticulously articles were screened with the subject relevancy and categorized for their ethnopharmacological significance with in-depth analysis. We have comprehensively elucidated the antiviral potency of phytoextracts, major composition, key compounds, mode of action, molecular evidence, immunological relevance, and potential bioactive phytocompounds of these five species belonging to the Zingiberaceae family. Conveniently, these phytoextracts exhibited multimode activity in combating the dreadful enveloped viruses.

Nephroprotective activity of Aframomum melegueta seeds extract against diclofenac-induced acute kidney injury: A mechanistic study

ETHNOPHARMACOLOGICAL RELEVANCE

In Africa, Aframomum species have been traditionally used to treat illnesses such as inflammation, hypertension, diarrhea, stomachache and fever. Moreover, Aframomum melegueta seed extracts (AMSE) are used in traditional medicine to relieve stomachaches and inflammatory diseases.

AIM

Chronic administration of diclofenac (DIC) has been reported to cause acute kidney injury (AKI), which is a serious health condition. The nephroprotective effect of AMSE is yet to be elucidated. Accordingly, this study aims to investigate the phytoconstituents of standardized AMSE, evaluate its nephroprotective effects against DIC-induced AKI in rats, and elaborate its underlying molecular mechanisms.

MATERIALS AND METHODS

The quantitative estimation of major AMSE constituents and profiling of its secondary metabolites were conducted via RP-HPLC and LC-ESI/Triple TOF/MS, respectively. Next, DIC (50 mg/kg)-induced AKI was achieved in Sprague-Dawley rats and DIC-challenged rats were administered AMSE (100 and 200 mg/kg) orally. All treatments were administered for five consecutive days. Blood samples were collected and the sera were used for estimating creatinine, urea and, kidney injury molecule (KIM)-1 levels. Kidney specimens were histopathologically assessed and immunohistochemically examined for c-Myc expression. A portion of the kidney tissue was homogenized and examined for levels of oxidative stress markers (MDA and GSH). Heme oxygenase (HO)-1, TNF-α, IL-6, Bax, Bcl2 and caspase-3 renal levels were quantified by ELISA. Moreover, the protein expression levels of NF-ҡB p65 was quantified using Western blot analysis, whereas mRNA expression levels of AMPK, SIRT-1, nuclear factor erythroid-2-related factor (Nrf2) and STAT3 were detected using qRT-PCR in the remaining kidney tissues.

RESULTS

Standardized AMSE was shown to primarily contain 6-gingerol, 6-shogaol and 6-paradol among the 73 compounds that were detected via LC-ESI/Triple TOF/MS including phenolic acids, hydroxyphenylalkanes, diarylheptanoids and fatty acids. Relative to DIC-intoxicated rats, AMSE modulated serum creatinine, urea, KIM-1, renal MDA, TNF-α, IL-6, Bax, and caspase-3 levels. AMSE has also improved renal tissue architecture, enhanced GSH and HO-1 levels, and upregulated renal Nrf2, AMPK, and SIRT-1 mRNA expression levels. Furthermore, AMSE suppressed NF-ҡB p65 protein and STAT3 mRNA expression, and further reduced c-Myc immunohistochemical expression in renal tissues. Overall, our findings revealed that AMSE counteracted DIC-induced AKI via its antioxidant, anti-inflammatory, and antiapoptotic activities. Moreover, AMSE activated Nrf2/HO1 and AMPK/SIRT1, and inhibited NF-ҡB/STAT3 signaling pathways. Therefore, AMSE is a promising agent for inhibiting DIC-induced nephrotoxicity.

Antibacterial Activity of Defatted and Nondefatted Methanolic Extracts of Aframomum melegueta K. Schum. against Multidrug-Resistant Bacteria of Clinical Importance

The antibacterial activity of the extracts of Aframomum melegueta including n-hexane extract (NHE), nondefatted methanol extract (NDME), and defatted methanol extract (DME) was investigated in this study. The NHE exhibited no antibacterial activity. The DME showed higher antibacterial activity than the NDME against the different isolates. At the highest concentration of 10 mg/mL in agar diffusion, NDME produced inhibition zones ranging from 11 to 29 mm against the microorganisms while DME produced inhibition zones ranging from 20 to 40 mm with the concentration of 10 mg/mL against the microorganisms. 0.1 mg/mL of the DME produced inhibition zones ranging between 12 and 14 mm in Aeromonas hydrophila ATCC 35654 and Pseudomonas aeruginosa ATCC 15442, respectively, while none of the isolates were inhibited by the NDME at a concentration of 1 mg/mL or less. In the agar dilution assay, the MICs of the NDME and DME ranged between 0.31 and 10 mg/mL, but more isolates were inhibited at 0.31 mg/mL of DME than those in NDME. In macrobroth assay, the MICs of the NDME ranged between 0.15 and 5.0 mg/mL and the MBCs ranged between 0.63 and 5.0 mg/mL, and the MICs of the DME ranged between 0.08 and 5.0 mg/mL and the MBCs were between 0.31 and 5.0 mg/mL. This study indicated that DME was more active with higher antibacterial activity than the NDME of this plant, and extracting the fatty portion of plant materials prior susceptibility testing would allow plant extracts to be more effective as well as justifying the use of Aframomum melegueta in traditional medicine for the treatment of bacterial infections.

Thirty days oral Aframomum melegueta extract elicited analgesic effect but influenced cytochrome p4501BI, cardiac troponin T, testicular alfa-fetoprotein and other biomarkers in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pain is the commonest symptom of a disease and the percentage of persons manifesting one form of pain is growing globally. Aframomum melegueta (AM) is commonly used by traditional doctors as medication for many ailments such as body pains and rheumatism because it possesses anti-inflammatory, anti-allergenic, antiviral, anti-ageing and anti-tumour phytochemical agents.

AIM OF THE STUDY

Traditionally a botanical remedy in the management of pain was assessed. A common tropical plant Aframomum melegueta (AM) was evaluated for the amelioration of pain. For further pharmacologic understanding sensitive marker were used to assess the effect of the extract on the organ as a multifaceted approach to the evaluation of safety and analgesic efficacy.

MATERIALS AND METHOD

Sensitive biomarkers such as troponin-T (CTnT), cardiac troponin-I (CTnI), interleukin-beta (IL-β), interleukin-6 (IL-6), tumor necrosis factor-alfa (TNF-α) were evaluated using the enzyme-linked immunosorbent assay (ELISA) method and electrocardiographic parameters were also evaluated. The dynamics of concentrations of the various subfamilies of cytochrome were also assessed using ELISA in the evaluation of thirty-day oral AM, while histopathological changes of organs were also observed.

RESULTS

Thirty-day oral AM doses 40 mg/kg and 80 mg/kg showed analgesic potential but influenced IL-6 level, IL-1β, TNF-α and P-LCR. Electrocardiographic parameters showed the extract had arrhythmogenic effects the other cardiac parameters influenced was CTnT. The testicular alfa-fetoprotein and prostate specific antigen were also influenced. There were also some histopathological changes.

CONCLUSIONS

The extract showed analgesic, anti-oxidant and anti-inflammatory potential with possible adverse effects consistent with testicular and prostate cancers, cardiovascular complication, hepatic congestion and cholestasis.

Anti-inflammatory activity of naturally occuring diarylheptanoids - A review

Inflammation involving the innate and adaptive immune systems is a normal response to infection. However, if it becomes uncontrolled, inflammation may result in autoimmune or auto inflammatory disorders, neurodegenerative diseases or cancers. The currently available anti-inflammatory drug therapy is often not successful or induces severe side effects. Thus, the search of new therapeutic options for the treatment of inflammation is highly required. Medicinal plants have been an interesting source for obtaining new active compounds. Diarylheptanoids characterized by a 1, 7-diphenylheptane structural skeleton, are a class of secondary plant metabolites that have gained increasing interest over the last few decades due to a wide variety of biological activities. This review covers 182 natural linear or macrocyclic diarylheptanoids described in the period of 1982 to 2020 with anti-inflammatory activities evaluated using quantified in vitro and/or in vivo assays. All of these data highlight the pharmacological potential of these natural compounds to act as anti-inflammatory drugs.

Protective effect of 6-paradol in acetic acid-induced ulcerative colitis in rats

Background

Ulcerative colitis is a gut inflammatory disorder due to altered immune response to gut microbiome, with interplay of environmental and genetic factors. TNF-α activates inflammatory response through a cascade of immune responses, augmenting pro-inflammatory mediators and proteases, activating chemotaxis, and infiltration of inflammatory cells, leading to ulceration and haemorrhage through cytotoxic reactive oxygen species. 6-Paradol, a dietary component in several plants belonging to the Zingiberaceae family, has shown anti-inflammatory and antioxidant activities. Current study evaluates the effect of 6-paradol in amelioration of ulcerative colitis in rats for the first time.

Methods

6-Paradol (95% purity) was obtained from seeds of Aframomum melegueta. Rats were divided randomly into six groups (n = 8). Group one was administered normal saline; group two was treated with the vehicle only; group three, sulfasalazine 500 mg/kg; and groups four, five, and six, were given 6-paradol (50, 100, 200, respectively) mg/kg orally through gastric gavage for 7 days. Colitis was induced on 4th day by intrarectal administration of 2 ml acetic acid (3%), approximately 3 cm from anal verge. On 8th day, rats were sacrificed, and distal one-third of the colon extending proximally up to 4 cm from anal orifice was taken for biochemical and gross examination. Two centimetres of injured mucosal portion was taken for histopathological investigations. SPSS (ver.26) was used for statistical analysis.

Results

Colonic and serum glutathione (GSH) levels decreased, while colonic and serum malondialdehyde (MDA), colonic myeloperoxidase (MPO) activity, serum interleukin-6 (IL-6), serum tumour necrosis factor-α (TNF-α) levels, and colon weight to length ratio were increased significantly in the colitis untreated group compared to normal control. Treatment with 6-paradol considerably improved all these parameters, especially at a dose of 200 mg/kg (p < 0.001), revealing non-significant differences with sulfasalazine 500 mg/kg and normal control (p = 0.998). Sulfasalazine and 6-paradol in a dose dependent manner also markedly reversed mucosal oedema, atrophy and inflammation, cryptic damage, haemorrhage, and ulceration. There were non-significant differences between low and medium doses and between medium and high doses of 6-paradol for IL-6 and serum MDA levels.

Conclusion

6-Paradol demonstrated protection against acetic acid-induced ulcerative colitis, probably by anti-inflammatory and antioxidant actions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03203-7.

Escin attenuates oxidative damage, apoptosis and lipid peroxidation in a model of cyclophosphamide-induced liver damage

To investigate the effects of escin (ES) on acute damage induced by alkylating agent, experimental rats were injected with cyclophosphamide (CPM) to cause liver damage. The animals were divided into four groups: Control Group, CPM (200 mg/kg), ES (10 mg/kg), CPM, and ES Groups. Immunohistopathological, hepatic histopathological, and biochemical changes were analyzed. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), malondyaldehyde (MDA), glutathion (GSH), total oxidant status (TOS) and total antioxidant status (TAS) in serum were all determined. Serum and immunohistopathology analysis revealed that MDA, ALT, AST, LDH, TOC and OSI, caspase-3 and Bax levels had increased while GSH, TAC, Bcl- 2 and OSI levels decreased in CPM Group when compared to Control Group. These findings appear to account for the severe damage detected. In the CPM + ES treated group, positive improvements were found in biochemical parameters as well as in cell-death and tissue-related damage parameters.The results show that ES considerably protects the rat liver against CPM-induced hepatotoxicity thanks to because of its anti-oxidant and anti-apoptotic properties.

Ethnobotanical survey, anthelmintic effects and cytotoxicity of plants used for treatment of helminthiasis in the Central and Kara regions of Togo

Background

Traditional medicines are the main source of treatment of helminthiasis in endemic areas of Togo. The present study aimed to investigate the plants used by Traditional healers (THs) to treat helminth infections in endemic communities within the Central and Kara regions of Togo and to evaluate the anthelmintic activity of the three most cited plants.

Methods

An ethnobotanical survey was conducted from 19 to 24 June 2017 among traditional healers in the Central and Kara regions of Togo. The anthelmintic activity of the most cited plants namely Aframomum melegueta K. Schum, Khaya senegalensis A. Juss and Xylopia aethiopica A. Rich, was evaluated using microfilariae (Mf) of Litomosoides sigmodontis. The plants were evaluated for cytotoxicity according to the recommendation of NF EN ISO 10993-5 standard using the propidium iodide (PI) dye by flow cytometry on human peripheral blood mononuclear cells.

Results

A total of 197 THs were interviewed and 41 plant species were recorded. Leguminosae (14.6%) and Annonaceae (9.7%) families constitute the highest number of species cited for treatment of helminth infections. Afromomum melegueta was the most cited by the THs for the treatment of onchocerciasis (UV = 0.036) while X. aethiopica was associated with the treatment of schistosomiasis (UV = 0.061) and lymphatic filariasis (UV = 0.061). There was a great agreement among the THs regarding ethnomedicinal uses of plants to treat helminthiasis with ICF values ranging from 0.57 to 0.67. The anthelmintic assay yielded lethal doses values of 233 μg/mL, 265 μg/mL and 550 μg/mL, respectively for X. aethiopica, A. melegueta and K. senegalensis. Afromomum melegueta and X. aethiopica presented no cytotoxicity, less than 20% death, whereas K. senegalensis induced moderate toxicity, 24 ± 8% death.

Conclusion

This study demonstrated the scientific rationale for the use of plants to treat helminthiasis in the Togolese traditional medicine. However, the use of K. senegalensis requires more caution since the plant is fairly toxic.

Trial Registration

NA

Anti-adhesive activity of Aframomum melegueta major phenolics on lower respiratory tract pathogens

Recent studies have raised interest in the potential health effect of Aframomum melegueta, which is related to the phenolic content of its seeds. The methanolic extract of A. melegueta seeds showed a significant anti-adhesive effect against Staphylococcus aureus to lung carcinoma cell line in a concentration-dependent manner. The n-butanol and the chloroform fractions exhibited a significant antiadhesive activity against S. aureus. The chloroform fraction exhibited an antiadhesive effect of 49.53%, 40.15% and 70.34% at concentrations 25, 50 and 100 µg/mL, respectively. Through a biologically guided isolation, the chloroform fraction yielded a new diarylheptanoid identified using 1D, 2D NMR and HREIMS and named 3-(S)-acetyl-1-(4',5'-dihydroxy-3'- methoxyphenyl)-7-(3″,4″-dihydroxyphenyl)heptane(1), in addition to eight known compounds (2-9). Compounds (1), 6-paradol (5), [6]-shogaol (7), [8]-gingerol(8) and dihydro[6]paradol (9) exhibited a significant anti-adhesive activity against S. aureus with a % of inhibition of adhesion of 60.58, 50, 70.07, 85.4, 59.85% at 50 µg/mL, respectively. Additionally, the extract's capacity to reduce adhesion without reducing bacterial growth reduces the likeliness of resistance development.

Comparative pathogenicity of two subtypes (hepatitis-type and pancreatitis-type) of duck hepatitis A virus type 1 in experimentally infected Muscovy ducklings

Duck hepatitis A virus type 1 (DHAV-1) causes acute hepatitis with high morbidity and mortality in ducklings of the genera Cairina and Anas and is characterized by ecchymotic haemorrhage and necrosis of the liver surface. Since September 2011, a new subtype of DHAV-1 (named pancreatitis-type DHAV-1) has been isolated. This new subtype is characterized by yellowish or haemorrhagic pancreatitis, but with no significant pathological changes in the liver. To further investigate the difference in pathogenicity between hepatitis-type DHAV-1 and pancreatitis-type DHAV-1, we infected Muscovy ducklings with a hepatitis-type DHAV-1 strain, FZ86, or a pancreatitis-type DHAV-1 strain, MPZJ1206, and then compared the resulting gross lesions, histopathological changes, viral distribution and cellular apoptosis in the liver and pancreas of Muscovy ducklings. The results suggested that FZ86 induced a more efficient viral propagation in the liver than MPZJ1206, and the gross and histopathological lesions were also limited to the liver. However, MPZJ1206 induced more effective viral replication in the pancreas than FZ86. The MPZJ1206-infected Muscovy ducklings showed an obviously yellowed and haemorrhagic pancreas, but with no significant pathological changes in the liver. Furthermore, FZ86 induced notable hepatocyte apoptosis and increased the expression of caspase-3 in the liver, whereas MPZJ1206 caused apoptosis in a large number of acinar epithelial cells and elevated the expression of caspase-3 in the pancreas. Taken together, these results demonstrated that pancreatitis-type DHAV-1 has many new pathogenic features which distinguish it from the hepatitis-type DHAV-1. RESEARCH HIGHLIGHTS Pancreatitis-type DHAV-1 (MPZJ1206) was characterized by pancreatic haemorrhage and yellow discolouration, but with no obvious haemorrhage and necrosis in the liver. Pancreatitis-type DHAV-1 (MPZJ1206) exhibits many new pathogenic features which distinguish it from the hepatitis-type DHAV-1 (FZ86).

Cytokine storms are primarily responsible for the rapid death of ducklings infected with duck hepatitis A virus type 1

Duck hepatitis A virus type 1 (DHAV-1) is one of the most harmful pathogens in the duck industry. The infection of adult ducks with DHAV-1 was previously shown to result in transient cytokine storms in their kidneys. To understand how DHAV-1 infection impacts the host liver, we conducted animal experiments with the virulent CH DHAV-1 strain and the attenuated CH60 commercial vaccine strain. Visual observation and standard hematoxylin and eosin staining were performed to detect pathological damage in the liver, and viral copy numbers and cytokine expression in the liver were evaluated by quantitative PCR. The CH strain (108.4 copies/mg) had higher viral titers than the CH60 strain (104.9 copies/mg) in the liver and caused ecchymotic hemorrhaging on the liver surface. Additionally, livers from ducklings inoculated with the CH strain were significantly infiltrated by numerous red blood cells, accompanied by severe cytokine storms, but similar signs were not observed in the livers of ducklings inoculated with the CH60 strain. In conclusion, the severe cytokine storm caused by the CH strain apparently induces hemorrhagic lesions in the liver, which might be a key factor in the rapid death of ducklings.

Rapid Screening of Volatile Organic Compounds from Aframomum danielli Seeds Using Headspace Solid Phase Microextraction Coupled to Gas Chromatography Mass Spectrometry

Volatile organic compounds (VOCs) derived from plants have been used in the fragrance industry since time immemorial. Herein we report on the rapid screening of VOCs from seeds of ripe Aframomum danielli (family, Zingiberaceae) using a polydimethylsiloxane fibre headspace solid phase microextraction coupled to a gas chromatography mass spectrometry (SPME-GC/MS) instrument. Portions of 0.25, 0.35, and 0.50 g of ground sample were weighed and extraction of volatile organic compounds (VOCs) was achieved using a 100 μm polydimethylsiloxane solid phase microextraction (PDMS SPME) fibre, with the equilibrium time of 40 minutes and extraction temperature of 50°C; the following compounds with their respective relative abundances were obtained as the top ten most abundant and annotated ones using NIST, Wiley, and Fragrances Libraries: eucalyptol (58%); β-pinene (22%); α-pinene (7.5%); α-terpineol (4%), α-terpinyl acetate (2%); α-bergamotene (1%); pinocarveol (0.39%); α-copaene (0.35%); caryophyllene (0.34); and β-bisabolene (0.31%). These compounds have been reported elsewhere in the literature and listed in the Fragrances Library, incorporated into the Saturn QP2020 GCMS Solution® software used for their analysis.

Inhibition of key enzymes linked to type 2 diabetes by compounds isolated from Aframomum melegueta fruit

CONTEXT

The use of Aframomum melegueta K. Schum. (Zingiberaceae) fruit for treatment of diabetes has recently been established in Nigeria. However, compounds responsible for the antidiabetic action have not been identified.

OBJECTIVE

The present study carried out the bioassay-guided isolation of possible bioactive compounds responsible for the antidiabetic action of A. melegueta fruit.

MATERIALS AND METHODS

The A. melegueta fruit was sequentially extracted using ethyl acetate (EtOAc), ethanol and water, and the most active extract (EtOAc) was subjected to column chromatography on a silica gel column using solvent gradient systems of hexane (HEX):EtOAc and EtOAc:MeOH and the isolation of compounds was guided by α-glycosidase and α-amylase inhibitory activities at various concentrations (30-240 μg/mL).

RESULTS

According to the results, 3 arylalkanes, 6-paradol (1), 6-shogaol (2) and 6-gingerol (3) and a pentacyclic triterpene, oleanolic acid (4) were isolated from A. melegueta fruit. All the compounds exhibited inhibitory effects against α-amylase and α-glucosidase. 6-Gingerol (3) and oleanolic acid (4) showed higher inhibitory activity against α-amylase (IC50: 6-gingerol: 81.78 ± 7.79 μM; oleanolic acid: 91.72 ± 1.63 μM) and α-glucosidase (IC50: 6-gingerol: 21.55 ± 0.45 μM; oleanolic acid: 17.35 ± 0.88 μM) compared to the standard drug, acarbose and other isolated compounds. The kinetics of the enzyme action of the compounds showed a noncompetitive mode of inhibition.

CONCLUSION

The data of this study suggest that the 6-gingerol (3) and oleanolic acid (4) showed higher α-amylase and α-glucosidase inhibitory action and therefore could be responsible for the antidiabetic activity of A. melegueta fruit.

Phenolics Isolated from Aframomum meleguta Enhance Proliferation and Ossification Markers in Bone Cells

Osteoporosis is a serious health problem characterized by decreased bone mineral density and deterioration of bone microarchitecture. Current antiosteoporotic agents exhibit a wide range of adverse effects; meanwhile, phytochemicals are effective and safer alternatives. In the current work, nine compounds belonging to hydroxyphenylalkane and diarylheptanoid groups were isolated from Aframomum meleguea seeds and identified as 6-gingerol (1), 6-paradol (2), 8-dehydrogingerdione (3), 8-gingerol (4), dihydro-6-paradol (5), dihydrogingerenone A (6), dihydrogingerenone C (7), 1,7-bis(3,4-dihydroxy-5-methoxyphenyl)heptane-3,5-diyl diacetate (8), and 1-(3,4-dihydroxy-5-methoxyphenyl)-7-(3,4-dihydroxyphenyl)heptane-3,5-diyl diacetate (9). The structures of isolated compounds were established by NMR and mass spectral data, in addition to referring to literature data. Exposure of MCF-7, MG-63, and SAOS-2 cells to subcytotoxic concentrations of the compounds under investigation resulted in accelerated proliferation. Among them, paradol was selected for further detailed biochemical analysis in SAOS-2 cells. DNA flowcytometric analysis of cell cycle distribution revealed that paradol did not induce any significant change in the proliferation index of SAOS-2 cells. Assessment of osteogenic gene expression revealed that paradol enhanced the expression of osteocyte and osteoblast-related genes and inhibited osteoclast and RUNX suppressor genes. Biochemically, paradol enhanced alkaline phosphatase activity and vitamin D content and decreased the osteoporotic marker acid phosphatase. In conclusion, paradol, which is a major constituents of A. melegueta seeds, exhibited potent proliferative and ossification characteristics in bone cells.

Protective effects of gingerol on streptozotocin-induced sporadic Alzheimer's disease: emphasis on inhibition of β-amyloid, COX-2, alpha-, beta - secretases and APH1a

Gingerol is a major dietary compound that occurs in several plants belonging to the Zingiberaceae family. In the current study, the protective effect of gingerol on STZ-induced sporadic Alzheimer's disease (SAD) was determined. Gingerol was isolated from the seeds of Aframomum melegueta K. Schum and tested at doses of 10 and 20 mg/kgbwt for its possible effect on the SAD model in mice, using celecoxib (30 mg/kg bwt) as a reference standard. The curative effects of gingerol were assessed through measurement of β-amyloid (Aβ-42), α-, β- secretases, APH1a and COX-2 levels. In addition, improvement in the cognitive deficit in mice after treatment was confirmed using the water maze and Y-maze with intra-maze cues. Gingerol improved the cognitive and behavioral impairment and AD-like pathology in streptozotocin model mice. These beneficial effects occurred with an increase in α-secretase activity and a decrease in cerebral Aβ-42, β- secretase, APH1a activity and COX-2-linked neuro-inflammation.

Research progress in phytochemistry and biology of Aframomum species

CONTEXT

The African genus Aframomum (Zingiberaceae) is a group of diverse tropical plants frequently collected yet largely neglected taxonomically. The current and unprecedented loss of species due to man-made habitat destruction and climate change adds a desperate urgency not only to understand the phylogenetics, chemotaxonomy and biology, but also to preserve the quickly disappearing species.

OBJECTIVES

The present systematic review reports on the research progress in phytochemistry, pharmacology and toxicology of Aframomum species.

METHODOLOGY

Scientific databases such as MedSci, PubMed, Scopus, Google Scholar and Web of Knowledge were used to retrieve publications (from the year 1990 to 2014) related to Aframomum plants, isolated compounds and their bioactivity, phytochemistry and toxicology. The keywords combinations for the search were: Aframomum; chemotaxonomy, phylogenetics, pharmacology and bioactive metabolites and toxicology. A total of 71 research articles that report on the biological activity of extracts and chemical constituents were recovered and presented in this review.

RESULTS

Most published data related to the potential of Aframomum melegueta, a medicinal plant from West and Central Africa. The potential of phenols and terpenoids isolated from Aframomum plants were generally much better documented than that of arylalkanoids.

CONCLUSION

Aframomum genus represents an enormous resource for novel compounds with a range of medicinal properties. However, these plants are under-researched and their conservation is poor. To unravel their full potential, efforts should be strengthened throughout the continent to establish the taxonomy, preserve the genus and explore novel medicinal properties.

Gingerol Synergizes the Cytotoxic Effects of Doxorubicin against Liver Cancer Cells and Protects from Its Vascular Toxicity

Hydroxyphenylalkanes and diarylheptanoids possess potential therapeutic value in different pathophysiological conditions, such as malignancy. In the current study, naturally isolated hydroxyphenylalkane and diarylheptanoid compounds were investigated for potential chemo-modulatory effects in addition to potential vascular protective roles with doxorubicin. Diarylheptanoids showed stronger antioxidant effects, in comparison to hydroxyphenylalkanes, as demonstrated by DPPH assay and amelioration of CCl₄-induced disturbed intracellular GSH/GSSG balance. Shogaol and 4′-methoxygingerol showed considerable cytotoxic effects against HCT116, HeLa, HepG2 and MCF7 cells, with IC₅₀ values ranging from 3.1 to 19.4 µM. Gingerol significantly enhanced the cytotoxic profile of doxorubicin against HepG₂ and Huh7, cells decreasing its IC₅₀s by 10- and 4-fold, respectively. Cell cycle distribution was studied using DNA cytometry. Doxorubicin alone induced cell accumulation at S-phase and G₂/M-phase, while in combination with gingerol it significantly induced cell cycle arrest at the G₂/M-phase. Additionally, the vascular protective effect of gingerol against doxorubicin (10 µM) was examined on isolated aortic rings. Co-incubation with 6-gingerol (30 µM) completely blocked the exaggerated vasoconstriction and impaired vascular relaxation induced by doxorubicin. In conclusion, despite its relatively weak antioxidant properties, gingerol protected from DOX-induced vascular damage, apparently not through a ROS scavenging mechanism. Besides, gingerol synergized the cytotoxic effects of DOX against liver cancer cells without influencing the cellular pharmacokinetics.

Macrophage Migration Inhibitor Factor Upregulates MCP-1 Expression in an Autocrine Manner in Hepatocytes during Acute Mouse Liver Injury

Macrophage migration inhibitor factor (MIF), a multipotent innate immune mediator, is an upstream component of the inflammatory cascade in diseases such as liver disease. Monocyte chemoattractant protein-1 (MCP-1), a highly representative chemokine, is critical in liver disease pathogenesis. We investigated the role of MIF in regulating hepatocytic MCP-1 expression. MIF and MCP-1 expression were characterized by immunochemistry, RT-PCR, ELISA, and immunoblotting in CCl₄-treated mouse liver and isolated hepatocytes. MIF was primarily distributed in hepatocytes, and its expression increased upon acute liver injury. Its expression was also increased in injured hepatocytes, induced by LPS or CCl₄, which mimic liver injury in vitro. MIF was expressed earlier than MCP-1, strongly inducing hepatocytic MCP-1 expression. Moreover, the increase in MCP-1 expression induced by MIF was inhibited by CD74- or CD44-specific siRNAs and SB203580, a p38 MAPK inhibitor. Further, CD74 or CD44 deficiency effectively inhibited MIF-induced p38 activation. MIF inhibitor ISO-1 reduced MCP-1 expression and p38 phosphorylation in CCl₄-treated mouse liver. Our results showed that MIF regulates MCP-1 expression in hepatocytes of injured liver via CD74, CD44, and p38 MAPK in an autocrine manner, providing compelling information on the role of MIF in liver injury, and implying a new regulatory mechanism for liver inflammation.

Supplementation of fresh ucche (Momordica charantia L. var. muricata Willd) prevented oxidative stress, fibrosis and hepatic damage in CCl4 treated rats

Background

Ucche (Momordica charantia L. var. muricata (Willd.) Chakravarty) has been reported to possess many benefits and medicinal properties. However, the protective effect of ucche against carbon tetrachloride (CCl₄) induced hepatotoxicity have not been clarified fully yet. The aim of the present study was to investigate the effects of ucche on oxidative stress and inflammation in liver of CCl₄ treated rats.

Methods

Female Long Evans rats were administered with CCl₄ orally (1 ml/kg) twice a week for 2 weeks and were supplemented with freshly prepared crashed ucche (10% wt/wt of diet) with powdered chaw food. Both plasma and liver tissues were analyzed for AST, ALT and ALP activities. Oxidative stress parameters were measure by determining malondialdehyde (MDA), nitric oxide (NO), advanced protein oxidation product (APOP), and reduced glutathione (GSH) concentrations and catalase activities in plasma and liver tissues. Moreover, inflammation and tissue fibrosis were confirmed by histological staining of liver tissue sections.

Results

Our data suggest that ucche significantly prevented CCl₄-induced hepatotoxicity, indicated by both diagnostic indicators of liver damage (serum transferases activities) and histopathological analysis. Moreover, CCl₄ administration induced profound elevation of reactive oxygen species (ROS) production and oxidative stress, as evidenced by increasing lipid peroxidation level and depletion of antioxidant enzymes in liver. Fresh ucche supplementation prevented the oxidative stresses and improved antioxidant enzyme function. Furthermore, fresh ucche supplementation reduced hepatic inflammatory cell infiltration, iron deposition and fibrosis in liver of CCl₄ treated rats.

Conclusion

In conclusion, these results suggested that the inhibition of CCl₄-induced inflammation by ucche is due at least in part to its anti-oxidant activity and its ability to modulate the inflammation and fibrosis in liver.