Epidural Injection of Harpagoside for the Recovery of Rats with Lumbar Spinal Stenosis

Epidural administration is the leading therapeutic option for the management of pain associated with lumbar spinal stenosis (LSS), which is characterized by compression of the nerve root due to narrowing of the spinal canal. Corticosteroids are effective in alleviating LSS-related pain but can lead to complications with long-term use. Recent studies have focused on identifying promising medications administered epidurally to affected spinal regions. In this study, we aimed to investigate the effectiveness of harpagoside (HAS) as an epidural medication in rats with LSS. HAS at various concentrations was effective for neuroprotection against ferrous sulfate damage and consequent promotion of axonal outgrowth in primary spinal cord neurons. When two concentrations of HAS (100 and 200 μg/kg) were administered to the rat LSS model via the epidural space once a day for 4 weeks, the inflammatory responses around the silicone block used for LSS were substantially reduced. Consistently, pain-related factors were significantly suppressed by the epidural administration of HAS. The motor functions of rats with LSS significantly improved. These findings suggest that targeted delivery of HAS directly to the affected area via epidural injection holds promise as a potential treatment option for the recovery of patients with LSS.

Imatinib and methazolamide ameliorate COVID-19-induced metabolic complications via elevating ACE2 enzymatic activity and inhibiting viral entry

Coronavirus disease 2019 (COVID-19) represents a systemic disease that may cause severe metabolic complications in multiple tissues including liver, kidney, and cardiovascular system. However, the underlying mechanisms and optimal treatment remain elusive. Our study shows that impairment of ACE2 pathway is a key factor linking virus infection to its secondary metabolic sequelae. By using structure-based high-throughput virtual screening and connectivity map database, followed with experimental validations, we identify imatinib, methazolamide, and harpagoside as direct enzymatic activators of ACE2. Imatinib and methazolamide remarkably improve metabolic perturbations in vivo in an ACE2-dependent manner under the insulin-resistant state and SARS-CoV-2-infected state. Moreover, viral entry is directly inhibited by these three compounds due to allosteric inhibition of ACE2 binding to spike protein on SARS-CoV-2. Taken together, our study shows that enzymatic activation of ACE2 via imatinib, methazolamide, or harpagoside may be a conceptually new strategy to treat metabolic sequelae of COVID-19.

The protective effect of harpagoside on angiotensin II (Ang II)-induced blood-brain barrier leakage in vitro

Hypertension and its associated dysfunction of the blood-brain barrier (BBB) contribute to cerebral small vessel disease (cSVD). Angiotensin II (Ang II), a vasoactive peptide of the renin-angiotensin system (RAS), is not only a pivotal molecular signal in hypertension but also causes BBB leakage, cSVD, and cognitive impair. Harpagoside, the major bioactive constituent of Scrophulariae Radix, has been commonly used for the treatment of multiple diseases including hypertension in China. The effect of harpagoside on Ang II-induced BBB damage is unclear. We employed an immortalized endothelial cell line (bEnd.3) to mimic a BBB monolayer model in vitro and investigated the effect of harpagoside on BBB and found that harpagoside alleviated Ang II-induced BBB destruction, inhibited Ang II-associated cytotoxicity in a concentration-dependent manner and attenuated Ang II-induced reactive oxygen species (ROS) impair by downregulation of Nox2, Nox4, and COX-2. Harpagoside prevented Ang II-induced apoptosis via keeping Bax/Bcl-2 balance, decreasing cytochrome c release, and inactivation of caspase-8, caspase-9, and caspase-3 (the mitochondria-dependent and death receptor-mediated apoptosis pathways). Moreover, harpagoside can alleviate Ang II-induced BBB damage through upregulation of tight junction proteins and decrease of caveolae-mediated endocytosis. Thus, harpagoside might be a potential drug to treat Ang II-induced cSVD.

From Bush Medicine to Modern Phytopharmaceutical: A Bibliographic Review of Devil's Claw (Harpagophytum spp.)

Devil's claw (Harpagophytum spp., Pedaliaceae) is one of the best-documented phytomedicines. Its mode of action is largely elucidated, and its efficacy and excellent safety profile have been demonstrated in a long list of clinical investigations. The author conducted a bibliographic review which not only included peer-reviewed papers published in scientific journals but also a vast amount of grey literature, such as theses and reports initiated by governmental as well as non-governmental organizations, thus allowing for a more holistic presentation of the available evidence. Close to 700 sources published over the course of two centuries were identified, confirmed, and cataloged. The purpose of the review is three-fold: to trace the historical milestones in devil's claw becoming a modern herbal medicine, to point out gaps in the seemingly all-encompassing body of research, and to provide the reader with a reliable and comprehensive bibliography. The review covers aspects of ethnobotany, taxonomy, history of product development and commercialization, chemistry, pharmacology, toxicology, as well as clinical efficacy and safety. It is concluded that three areas stand out in need of further investigation. The taxonomical assessment of the genus is outdated and lacking. A revision is needed to account for intra- and inter-specific, geographical, and chemo-taxonomical variation, including variation in composition. Further research is needed to conclusively elucidate the active compound(s). Confounded by early substitution, intermixture, and blending, it has yet to be demonstrated beyond a reasonable doubt that both (or all) Harpagophytum spp. are equally (and interchangeably) safe and efficacious in clinical practice.

Changes in the Harpagide, Harpagoside, and Verbascoside Content of Field Grown Scrophularia lanceolata and Scrophularia marilandica in Response to Season and Shade

Scrophularia lanceolata Pursh and Scrophularia marilandica L. are two common species within the Scrophulariaceae family that are endemic to North America. Historically, these species were used by indigenous peoples and colonialists to treat sunburn, sunstroke, frostbite, edema, as well as for blood purification, and in women's health. Several iridoid and phenylethanoid/phenylpropanoid glycosides detected in these species, such as harpagoside and verbascoside, possess anti-inflammatory and anti-nociceptive properties. Due to the presence of anti-inflammatory metabolites and the historical uses of these species, we performed a two-year field study to determine the optimal production of these important compounds. We subjected the plants to shade treatment and analyzed differences in the metabolite composition between the two species and each of their leaves, stems, and roots at various times throughout the growing seasons. We determined that S. lanceolata plants grown in full sun produced 0.63% harpagoside per dried weight in their leaves compared to shade-grown plants (0.43%). Furthermore, S. lanceolata accumulated more harpagoside than S. marilandica (0.24%). We also found that verbascoside accumulated in the leaves of S. lanceolata and S. marilandica as the growing season progressed, while the production of this metabolite remained mostly seasonally unchanged in the roots of both species.

[Study on scrophulariaceae radix reference extract and its application in quality control of Scrophulariae Radix]

By establishing the preparation process of Scrophulariaceae Radix reference extract(SRRE) and calibrating it, we discussed its feasibility as a substitute for single reference substance in the quality control of Scrophulariae Radix. The SRREs were prepared by solvent extraction method and chromatographic separation technology, and then calibrated with the reference substances of harpagide, angoroside C and harpagoside. The HPLC content determination method of Scrophulariae Radixl was established with SRREs of the known content and the reference substances of harpagide, angoroside C and harpagoside respectively as the control ones. Then the content of three components in Scrophulariae Radix was determined, and the t-test method was used to compare the results of the two methods. With SRRE as references, harpagide, angoroside C and harpagoside were in a good linear relationship(r≥0.999 8) within each range, and the average recovery rate was 98.55% to 100.6%. The t-test results showed that the P values of two determination methods were 0.493, 0.155 and 0.171 for harpagide, angoroside C and harpagoside respectively, indicating no significant diffe-rence between the two methods of content determination. The SRRE can be used as a substitute for the reference in the quality control of Scrophulariaceae Radix. The SRRE can replace the corresponding reference substance for the quality control of Scrophulariae Radix. The results of this study provide new methods and new ideas for the quality evaluation of Scrophulariae Radix, and provide a scientific basis for the application of reference extracts in the quality research of traditional Chinese medicine.

Determination and Pharmacokinetic Profiles of Four Active Components From Scrophularia ningpoensis Hemsl. in Rats

Acteoside, angoroside C, harpagoside, and cinnamic acid, which are the main bioactive ingredients of Scrophularia ningpoensis Hemsl., have wide clinical use with various biological effects. A new and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established with taxifolin as the internal standard (IS) in this study and was successfully used to study the pharmacokinetic profiles of four active components from S. ningpoensis Hemsl. in rats after sublingual intravenous administration. After protein precipitation with acetonitrile, the mobile phase (consisting of acetonitrile and 0.1% formic acid) was used to separate the analytes on an Acquity UPLC BEH C18 chromatography column (2.1 × 50 mm, 1.7 μm) under gradient elution. The precursor-to-product ion transitions of 623.4 → 161.3 m/z for acteoside, 783.5 → 175.0 m/z for angoroside C, 493.3 → 345.2 m/z for harpagoside and 147.2 → 103.4 m/z for cinnamic acid were monitored by mass spectrometry with negative electrospray ionization in the multiple reaction monitoring (MRM) mode. The concentration range of 10–1,000 ng/ml could be detected by this method with a lower limit of quantification (LLOQ) of 10 ng/ml for each analyte. The intra- and inter-day precision (RSD%) of the method ranged from 2.6 to 9.9% and 2.7–11.5%, respectively. Meanwhile, the accuracy (RE%) was −9.6–10.7% in this developed method. The mean recoveries of four active components from S. ningpoensis Hemsl. were more than 76.7% with negligible matrix effects. The four active components from S. ningpoensis Hemsl. were stable under multiple storage and process conditions. A new, sensitive and simple analytical method had been established and was successfully applied to the pharmacokinetic profiles of four active components from S. ningpoensis Hemsl. in rats after sublingual intravenous administration.

Three Scrophularia Species (Scrophularia buergeriana, S. koraiensis, and S. takesimensis) Inhibit RANKL-Induced Osteoclast Differentiation in Bone Marrow-Derived Macrophages

Scrophulariae Radix, derived from the dried roots of Scrophularia ningpoensis Hemsl. or S. buergeriana Miq, is a traditional herbal medicine used in Asia to treat rheumatism, arthritis, and pharyngalgia. However, the effects of Scrophularia buergeriana, S. koraeinsis, and S. takesimensis on osteoclast formation and bone resorption remain unclear. In this study, we investigated the morphological characteristics and harpagoside content of S. buergeriana, S. koraiensis, and S. takesimensis, and compared the effects of ethanol extracts of these species using nuclear factor (NF)-κB ligand (RANKL)-mediated osteoclast differentiation. The harpagoside content of the three Scrophularia species was analyzed by high-performance liquid chromatography–mass spectrometry (HPLC/MS). Their therapeutic effects were evaluated by tartrate-resistant acid phosphatase (TRAP)-positive cell formation and bone resorption in bone marrow-derived macrophages (BMMs) harvested from ICR mice. We confirmed the presence of harpagoside in the Scrophularia species. The harpagoside content of S. buergeriana, S. koraiensis, and S. takesimensis was 1.94 ± 0.24 mg/g, 6.47 ± 0.02 mg/g, and 5.50 ± 0.02 mg/g, respectively. Treatment of BMMs with extracts of the three Scrophularia species inhibited TRAP-positive cell formation in a dose-dependent manner. The area of hydroxyapatite-absorbed osteoclasts was markedly decreased after treatment with the three Scrophularia species extracts. Our results indicated that the three species of the genus Scrophularia might exert preventive effects on bone disorders by inhibiting osteoclast differentiation and bone resorption, suggesting that these species may have medicinal and functional value.

[Isolation and identification of endophytic fungi producing harpagoside and harpagide from Scrophularia ningpoensis]

The endophytic fungi from root,main stem,branch and leaf of Scrophularia ningpoensis were isolated from Zhejiang,whether these strains could yield harpagide or harpagoside were tested by HPLC and LC-MS. According to the morphological characteristic and the similarity of the nucleotide sequence of internal transcribed spacer( ITS) between r DNAs,the strains producing harpagide or harpagoside were identified. The results showed that 210 strains were isolated from the samples,which were classified into 9 orders,13 families and 17 genera by morphological study. Harpagide was detected in endogenous fungi ZJ17 and harpagoside was detected in endogenous fungi ZJ25 by HPLC coupled with LC-MS. ZJ17 was identified as Alternaria alternate and ZJ25 was identified as A.gaisen by its morphology and authenticated by ITS( ITS4 and ITS5 regions and the intervening 5. 8 S rDNA region).

Targeting Quorum Sensing: High-Throughput Screening to Identify Novel LsrK Inhibitors

Since quorum sensing (QS) is linked to the establishment of bacterial infection, its inactivation represents one of the newest strategies to fight bacterial pathogens. LsrK is a kinase playing a key role in the processing of autoinducer-2 (AI-2), a quorum-sensing mediator in gut enteric bacteria. Inhibition of LsrK might thus impair the quorum-sensing cascade and consequently reduce bacterial pathogenicity. Aiming for the development of a target-based assay for the discovery of LsrK inhibitors, we evaluated different assay set-ups based on ATP detection and optimized an automation-compatible method for the high-throughput screening of chemical libraries. The assay was then used to perform the screening of a 2000-compound library, which provided 12 active compounds with an IC₅₀ ≤ 10 µM confirming the effectiveness and sensitivity of our assay. Follow-up studies on the positive hits led to the identification of two compounds, harpagoside and rosolic acid, active in a cell-based AI-2 QS interference assay, which are at the moment the most promising candidates for the development of a new class of antivirulence agents based on LsrK inhibition.

Harpagoside Rescues the Memory Impairments in Chronic Cerebral Hypoperfusion Rats by Inhibiting PTEN Activity

Vascular dementia (VaD) is the second most common dementia worldwide. Unlike Alzheimer's disease, VaD does not yet have effective therapeutic drugs. Harpagoside is the most important component extracted from Harpagophytum procumbens, a traditional Chinese medicine that has been widely used. The neuroprotective effects of harpagoside have been studied in Aβ- and MPTP-induced neurotoxicity. However, whether harpagoside is protective against VaD is not clear. In this study, with the use of chronic cerebral hypoperfusion rats, a well-known VaD model, we demonstrated that chronic administration (two months) of harpagoside was able to restore both the spatial learning/memory and fear memory impairments. Importantly, the protective effects of harpagoside were not due to alterations in the physiological conditions, metabolic parameters, or locomotor abilities of the rats. Meanwhile, we found that harpagoside suppressed the overactivation of PTEN induced by CCH by enhancing PTEN phosphorylation. Furthermore, harpagoside elevated the activity of Akt and inhibited the activity of GSK-3β, downstream effectors of PTEN. Overall, our study suggested that harpagoside treatment might be a potential therapeutic drug targeting the cognitive impairments of VaD.

Quality Assessment of Commercial Spagyric Tinctures of Harpagophytum procumbens and Their Antioxidant Properties

Preparations from the dried tubers of Harpagophytum procumbens (Burch.) DC ex Meisn, commonly known as devil’s claw, are mainly used in modern medicine to relieve joint pain and inflammation in patients suffering from rheumatic and arthritic disorders. This paper describes for the first time the chemical profile of a commercial spagyric tincture (named 019) prepared from the roots of the plant. For comparison purposes, a commercial not-spagyric devil’s claw tincture (NST) was also analyzed. Chemical investigation of the content of specialized metabolites in the three samples indicated that harpagoside was the main compound, followed by the two isomers acteoside and isoacteoside. Compositional consistence over time was obtained by the chemical fingerprinting of another spagyric tincture (named 014) from the same producer that was already expired according to the recommendation on the label of the product. The two spagyric preparations did not show significant compositional differences as revealed by HPLC and MS analyses, except for a decrease in harpagide content in the expired 014 tincture. Moreover, their antioxidant capacities as assessed by 2,2’-di-phenyl-1-picrylhydrazyl (DPPH) and 2.2’-azin-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods resulted in very similar IC50 values. The expired 014 tincture showed instead a lower IC50 value compared to the 019 and NST tinctures with the ferric reducing antioxidant potential (FRAP) assay, indicating a higher ferric-reducing antioxidant ability. Overall, these results indicated that the two preparations could generally maintain good stability and biological activity at least for the four years from the production to the expiration date.

Pharmacokinetics of harpagoside in horses after intragastric administration of a Devil's claw (Harpagophytum procumbens) extract

Devil's claw is used for the treatment of inflammatory symptoms and degenerative disorders in horses since many years, but without the substantive pharmacokinetic data. The pharmacokinetic parameters of harpagoside, the main active constituent of Harpagophytum procumbens DC ex Meisn., were evaluated in equine plasma after administration of Harpagophytum extract FB 8858 in an open, single‐dose, two‐treatment, two‐period, randomized cross‐over design. Six horses received a single dose of Harpagophytum extract, corresponding to 5 mg/kg BM harpagoside, and after 7 days washout period, 10 mg/kg BM harpagoside via nasogastric tube. Plasma samples at certain time points (before and 0–24 hr after administration) were collected, cleaned up by solid‐phase extraction, and harpagoside concentrations were determined by LC‐MS/MS using apigenin‐7‐glucoside as internal standard. Plasma concentration‐time data and relevant parameters were described by noncompartmental model through PKSolver software. Harpagoside could be detected up to 9 hr after administration. C_max was found at 25.59 and 55.46 ng/ml, t_1/2 at 2.53 and 2.32 hr, respectively, and t_max at 1 hr in both trials. AUC_0–inf was 70.46 and 117.85 ng hr ml⁻¹, respectively. A proportional relationship between dose, C_max and AUC was observed. Distribution (V_z/F) was 259.04 and 283.83 L/kg and clearance (CL/F) 70.96 and 84.86 L hr⁻¹ kg⁻¹, respectively. Treatment of horses with Harpagophytum extract did not cause any clinically detectable side effects.

Discovery of the Linear Region of Near Infrared Diffuse Reflectance Spectra Using the Kubelka-Munk Theory

Particle size is of great importance for the quantitative model of the NIR diffuse reflectance. In this paper, the effect of sample particle size on the measurement of harpagoside in Radix Scrophulariae powder by near infrared diffuse (NIR) reflectance spectroscopy was explored. High-performance liquid chromatography (HPLC) was employed as a reference method to construct the quantitative particle size model. Several spectral preprocessing methods were compared, and particle size models obtained by different preprocessing methods for establishing the partial least-squares (PLS) models of harpagoside. Data showed that the particle size distribution of 125–150 μm for Radix Scrophulariae exhibited the best prediction ability with Rpre2 = 0.9513, RMSEP = 0.1029 mg·g⁻¹, and RPD = 4.78. For the hybrid granularity calibration model, the particle size distribution of 90–180 μm exhibited the best prediction ability with Rpre2 = 0.8919, RMSEP = 0.1632 mg·g⁻¹, and RPD = 3.09. Furthermore, the Kubelka-Munk theory was used to relate the absorption coefficient k (concentration-dependent) and scatter coefficient s (particle size-dependent). The scatter coefficient s was calculated based on the Kubelka-Munk theory to study the changes of s after being mathematically preprocessed. A linear relationship was observed between k/s and absorption A within a certain range and the value for k/s was >4. According to this relationship, the model was more accurately constructed with the particle size distribution of 90–180 μm when s was kept constant or in a small linear region. This region provided a good reference for the linear modeling of diffuse reflectance spectroscopy. To establish a diffuse reflectance NIR model, further accurate assessment should be obtained in advance for a precise linear model.

[Binding interaction of harpagoside and bovine serum albumin: spectroscopic methodologies and molecular docking]

Scrophularia ningpoensis has exhibited a variety of biological activities and been used as a pharmaceutical product for the treatment of inflammatory ailment, rheumatoid arthritis, osteoarthritis and so on. Harpagoside (HAR) is considerer as a main bioactive compound in this plant. Serum albumin has important physiological roles in transportation, distribution and metabolism of many endogenous and exogenous substances in body. It is of great significance to study the interaction mechanism between HAR and bovine serum albumin (BSA). The mechanism of interaction between HAR and BSA was investigated using 2D and 3D fluorescence, synchronous florescence, ultraviolet spectroscopy and molecular docking. According to the analysis of fluorescence spectra, HAR could strongly quench the fluorescence of BSA, and the static quenching process indicated that the decrease in the quenching constant was observed with the increase in temperature. The magnitude of binding constants (KA) was more than 1×10⁵ L·mol⁻¹, and the number of binding sites(n) was approximate to 1. The thermodynamic parameters were calculated through analysis of fluorescence data with Stern-Volmer and Van't Hoff equation. The calculated enthalpy change (ΔH) and entropy change (ΔS) implied that the main interaction forces of HAR with BSA were the bonding interaction between van der Waals forces and hydrogen. The negative values of energy (ΔG) demonstrated that the binding of HAR with BSA was a spontaneous and exothermic process. The binding distance(r) between HAR and BSA was calculated to be about 2.80 nm based on the theory of Frster's non-radiation energy transfer, which indicated that energy is likely to be transfer from BSA to HAR. Both synchronous and 3D florescence spectroscopy clearly revealed that the microenvironment and conformation of BSA changed during the binding interaction between HAR and BSA. The molecular docking analysis revealed HAR is more inclined to BSA and human serum albumin (HSA) in subdomain ⅡA (Sudlow's site I). This study will provide valuable information for understanding the action mechanism of HAR.

Harpagoside-induced anaphylactic reaction in an IgE-independent manner both in vitro and in vivo

BACKGROUND

Harpagoside (HAR) is an active component of Scrophularia ningpoensis (SN), which has anti-inflammatory and anti-immune effects. SN is used widely in China to treat various diseases. Recently, SN has been used as a traditional Chinese medicine injection and used clinically. However, allergic responses to these injections are frequently reported.

AIM

We examined whether the main component of SN, HAR, is associated with the allergic reaction to SN.

METHODS

This study assessed the effects of HAR in mice and mast cell activation to characterize its anaphylactic effects and underlying mechanisms. Mice hindpaw swelling, serum allergy factor detection, enzyme-linked immunosorbent assays, and degranulation assays were performed to measure allergic mediators both in vivo and in vitro.

RESULTS

The present study indicated that HAR induced paw swelling, interleukin-6, inositol triphosphate, tumor necrosis factor-α, and histamine increases in mice. Our in vitro data also showed that HAR induced β-hexosaminidase, inositol triphosphate, and interleukin-6 release, leading to mast cell degranulation. In contrast, neither C48/80 nor HAR induced local anaphylaxis in STOCK Kit^W-sh/HNihrJaeBsmJNju mice.

CONCLUSIONS

HAR is a potential sensitization compound in SN, and these results provide information for the safe clinical use of SN.

Harpagoside suppresses IL-6 expression in primary human osteoarthritis chondrocytes

There is growing evidence in support of the involvement of inflammatory response in the pathogenesis of osteoarthritis (OA). Harpagoside, one of the bioactive components of Harpagophytum procumbens (Hp), has been shown to possess anti-inflammatory properties. Here we used an in vitro model of inflammation in OA to investigate the potential of harpagoside to suppress the production of inflammatory cytokines/chemokines such as IL-6 and matrix degrading proteases. We further investigated the likely targets of harpagoside in primary human OA chondrocytes. OA chondrocytes were pre-treated with harpagoside before stimulation with IL-1β. mRNA expression profile of 92 cytokines/chemokines was determined using TaqMan Human Chemokine PCR Array. Expression levels of selected mRNAs were confirmed using TaqMan assays. Protein levels of IL-6 and MMP-13 were assayed by ELISA and immunoblotting. Total protein levels and phosphorylation of signaling proteins were determined by immunoblotting. Cellular localization of IL-6 and c-Fos was performed by immunofluorescence and confocal microscopy. DNA binding activity of c-FOS/AP-1 was determined by ELISA. Harpagoside significantly altered the global chemokine expression profile in IL-1β-stimulated OA chondrocytes. Expression of IL-6 was highly induced by IL-1β, which was significantly inhibited by pre-treatment of OA chondrocytes with harpagoside. Harpagoside did not inhibit the IL-1β-induced activation of NF-κB and C/EBPβ transcription factors but suppressed the IL-1β-triggered induction, phosphorylation, and DNA binding activity of c-FOS, one of the main components of AP-1 transcription factors. Further, harpagoside significantly inhibited the expression of MMP-13 in OA chondrocytes under pathological conditions. siRNA-mediated knockdown of IL-6 resulted in suppressed expression and secretion of MMP-13 directly linking the role of IL-6 with MMP-13 expression. Taken together, the present study suggests that harpagoside exerts a significant anti-inflammatory effect by inhibiting the inflammatory stimuli mediated by suppressing c-FOS/AP-1 activity in OA chondrocytes under pathological conditions. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:311-320, 2017.

Characterization of Antifungal Natural Products Isolated from Endophytic Fungi of Finger Millet (Eleusine coracana)

Finger millet is an ancient African-Indian crop that is resistant to many pathogens including the fungus, Fusarium graminearum. We previously reported the first isolation of putative fungal endophytes from finger millet and showed that the crude extracts of four strains had anti-Fusarium activity. However, active compounds were isolated from only one strain. The objectives of this study were to confirm the endophytic lifestyle of the three remaining anti-Fusarium isolates, to identify the major underlying antifungal compounds, and to initially characterize the mode(s) of action of each compound. Results of confocal microscopy and a plant disease assay were consistent with the three fungal strains behaving as endophytes. Using bio-assay guided fractionation and spectroscopic structural elucidation, three anti-Fusarium secondary metabolites were purified and characterized. These molecules were not previously reported to derive from fungi nor have antifungal activity. The purified antifungal compounds were: 5-hydroxy 2(3H)-benzofuranone, dehydrocostus lactone (guaianolide sesquiterpene lactone), and harpagoside (an iridoide glycoside). Light microscopy and vitality staining were used to visualize the in vitro interactions between each compound and Fusarium; the results suggested a mixed fungicidal/fungistatic mode of action. We conclude that finger millet possesses fungal endophytes that can synthesize anti-fungal compounds not previously reported as bio-fungicides against F. graminearum.

A new iridoid diglucoside from Harpagophytum procumbens

A new iridoid diglucoside has been isolated from an aqueous extract of Harpagophytum procumbens secondary roots, together with six known compounds. Its structure has been assigned as 6'-O-glucopyranosyl-8-O-trans-coumaroylharpagide by spectroscopic means.

Antimutagenic potential of harpagoside and Harpagophytum procumbens against 1-nitropyrene

Background:

1-nitropyrene (1-NPy) is one of the most abundant nitro-polycyclic aromatic hydrocarbons particularly in diesel exhausts. It is a mutagenic and carcinogenic pollutant very widespread in the environment. So the discovery of antimutagenic agents is essential. Harpagophytum procumbens (HP) is traditionally used as anti-inflammatory and analgesic particularly against painful osteoarthritis. Harpagoside (HS), its major iridoid glycoside, is considered as the main active component.

Objective:

The aim of the present study was to evaluate the antimutagenic activity of HS and HP extracts against mutagenic activity of 1-NPy.

Materials and Methods:

The antimutagenic activity was investigated using the in vitro cytokinesis-block micronucleus assay in cultured human lymphocytes. Cells were exposed to HS or HP extracts before (pretreatment), during (co-treatment), and after (posttreatment) treatment with 1-NPy.

Results:

Results showed that HS significantly reduced the mutagenicity of 1-NPy in pretreatment and particularly in co-treatment, whereas all HP extracts significantly reduced the genotoxicity in the three protocols.

Conclusion:

These results suggested that HS was strongly involved in antimutagenic activity of HP extracts in co-treatment, but other components in HP extracts participated in this activity in pre- and post-treatment.

Iridoid glycosides from Alonsoa meridionalis

A new iridoid glucoside has been isolated from the Chilean native Alonsoa meridionalis (L.f.) Kuntze. Its structure has been assigned as 6'-O-β-d-glucopyranosyl-8-O-acetylharpagide (1) by using spectroscopic methods. Harpagoside (2), laterioside (3) and verbascoside (4) were also identified.

Anatomical study of secondary tuberized roots of Harpagophytum procumbens DC and quantification of harpagoside by high-performance liquid chromatography method

Aim and Background:

A botanical study is conducted to provide a standard diagnostic tool. In order to improve the quality assurance of the secondary tuberized roots of Harpagophytum procumbens, derived extract and phytomedicine, a simple, rapid, and accurate high-performance liquid chromatography (HPLC) method was developed to assess the harpagoside.

Material and Mehods:

This HPLC assay was performed on a reversedphase C18 column with methanol and water (50/50–V/V) as the mobile phase with a flow rate of 1.5 mL/min and using a monitoring wavelength at 278 nm.

Results and Conclusion:

This method was successfully applied to quantify these bioactive iridoid in an aqueous extract of H. procumbens and in its related phytomedicine “harpagophyton”. The result demonstrated that the quantification of harpagoside, indicating that the quality control of the bioactive ingredient in H. procumbens, derived extract and phytomedicine, is critical to ensure its clinical benefits.