Anti-hypernociceptive effects of methanol extract of Boswellia dalzielii on STZ-induced diabetic neuropathic pain

Antioxidant and anti-inflammatory effects of Boswellia dalzielii and Hibiscus sabdariffa extracts in alloxan-induced diabetic rats

Diabetes mellitus (DM) is one of the leading worldwide public health problems. It is characterized by hyperglycemia which induces oxidative stress and inflammation, both involved in the pathogenesis of diabetes. We previously showed that Boswellia dalzielii (BD) and Hibiscus sabdariffa (HS) extracts reduced hyperglycemia and hyperlipidemia in alloxan-induced diabetic rats. In the present study, we evaluated the antioxidant and anti-inflammatory activities of both plants in alloxan-induced diabetic rats. Two sets of experiments were conducted in male Wistar rats subjected to a single intraperitoneal injection of alloxan monohydrate (150 mg/kg, b. w.). Then, diabetic rats were daily administered with either BD (1st set of experiments) or HS (2nd set of experiments) at 100, 200, and 400 mg/kg orally for 21 consecutive days. Glibenclamide (10 mg/kg) was also administered as a reference drug. At the end of the study, the animals were anesthetized, and blood samples were collected from each animal. Then, oxidative stress and inflammatory biomarkers in the serum were determined. We found that treatment with BD and HS significantly reduced malondialdehyde (MDA) and enhanced the levels of reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). These extracts also significantly decreased the inflammatory markers tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). From the results obtained, it can therefore be concluded that BD and HS have the potential to being developed as natural sources of antioxidant and anti-inflammatory agents that can be used for the prevention or treatment of DM.

A Nutritional Supplement as Adjuvant of Gabapentinoids for Adults with Neuropathic Pain following Spinal Cord Injury and Stroke: Preliminary Results

Gabapentinoids are first choice drugs for central neuropathic pain (CNP) despite limited evidence of efficacy and side effects affecting therapy outcomes. Nutraceuticals could improve their efficacy and tolerability. Our aim is to investigate the effect of NACVAN®, in addition to gabapentinoids, on pain symptomatology in CNP patients. The effect of 6 weeks of treatment of NACVAN® was preliminary observed among 29 adult inpatients with spinal cord injury (SCI) or stroke-related CNP recruited to the experimental group. Pain intensity, neuropathic pain, and quality-of-life were measured at baseline (T0) and after 3 (T1) and 6 weeks (T2). Change in each outcome over time was assessed through a repeated measures analysis of variance or Wilcoxon matched-pairs test. Preliminary results show a significant reduction in pain intensity (T0 → T1, p = 0.021; T0 → T2, p = 0.011; T1 → T2, p = 0.46), neuropathic symptoms (T0 → T1, p = 0.024; T0 → T2, p = 0.003), and evoked pain (T0 → T2, p = 0.048). There were no significant reductions in other neuropathic pain dimensions and in quality-of-life components. No side-effects were detected. NACVAN® could have a beneficial adjuvant effect when used as an add-on to gabapentinoids in patients suffering from CNP due to SCI or stroke, with no adverse effect. Future analysis on a larger sample, compared with a placebo condition, could confirm these preliminary results.

New verticillane-diterpenoid as potent NF-κB inhibitor isolated from the gum resin of Boswellia sacra

Two new verticillane-diterpenoids (1 and 2) were isolated from the gum resin Boswellia sacra. Their structures were elucidated by physiochemical and spectroscopic analysis, as well as ECD calculation. In addition, the in vitro anti-inflammatory activities of the isolated compounds were evaluated by determining the inhibitory effects on lipopolysaccharide (LPS)-induced NO production in RAW 264.7 mouse monocyte-macrophages. The results showed that compound 1 exhibited significant inhibitory effect on NO generation with an IC₅₀ value of 23.3 ± 1.7 μM suggesting that it might be a candidate for an anti-inflammatory agent. Furthermore, 1 potently inhibited the release of inflammatory cytokines IL-6 and TNF-α induced by LPS in a dose-dependent manner. Using Western blot and Immunofluorescence methods, compound 1 was found to inhibit inflammation mainly by restraining the activation of NF-κB pathway. And in the MAPK signaling pathway, it was found to have inhibitory effects on the phosphorylation of JNK and ERK proteins and have no effect on the phosphorylation of p38 protein.

Effects of Ziziphus Jujuba Extract Alone and Combined with Boswellia Serrata Extract on Monosodium Iodoacetate Model of Osteoarthritis in Mice

Background

As a chronic joint condition, osteoarthritis (OA) is a common problem among older people. Pain, aching, stiffness, swelling, decreased flexibility, reduced function, and disability are the symptoms of arthritis.

Objectives

In this study, we tested the extracts of Ziziphus jujuba (ZJE) and Boswellia serrata (BSE) to reduce OA symptoms as an alternative treatment.

Methods

NMRI mice were administered an intra-articular injection of monosodium iodoacetate (MIA; 1 mg/10 mL) in the left knee joint cavity for the induction of OA. Hydroalcoholic extracts of ZJE (250 and 500 mg/kg), BSE (100 and 200 mg/kg), and combined ZJE and BSE were orally administered daily for 21 days. Following behavioral tests, plasma samples were collected to detect inflammatory factors. To screen for general toxicity, acute oral toxicity was evaluated.

Results

Oral administration of all the hydroalcoholic extracts significantly increased the locomotor activity, pixel values of the foot-print area, paw withdrawal threshold, the latency of the withdrawal response to heat stimulation, and decreased the difference between pixel values of hind limbs compared to the vehicle group. Also, the elevated levels of IL-1β, IL-6, and TNF-α were reduced. As tested in this study, ZJE and BSE were practically nontoxic and had a high degree of safety.

Conclusions

This study demonstrated that the oral administration of ZJE and BSE slows the progression of OA through anti-nociceptive and anti-inflammatory properties. Oral co-administration of ZJE and BSE extracts can be used as herbal medicine to inhibit OA progression.

Atorvastatin prevents the development of diabetic neuropathic nociception by possible involvement of nitrergic system

AIMS

Diabetic neuropathy has been identified as a common complication caused by diabetes. However, its pathophysiological mechanisms are not fully understood yet. Statins, also known as HMG-CoA reductase inhibitors, alleviate the production of cholesterol. Despite this cholesterol-reducing effect of statins, several reports have demonstrated their beneficial properties in neuropathic pain. In this study, we used streptozotocin (STZ)-induced diabetic model to investigate the possible role of nitric oxide (NO) in the antineuropathic-like effect of atorvastatin.

METHODS

Diabetes was induced by a single injection of STZ. Male rats orally received different doses of atorvastatin for 21 days. To access the neuropathy process, the thermal threshold of rats was assessed using hot plate and tail-flick tests. Moreover, sciatic motor nerve conduction velocity (MNCV) studies were performed. To assess the role of nitric oxide, N(G)-nitro-L-arginine methyl ester (L-NAME), aminoguanidine (AG), and 7-nitroindazole (7NI) were intraperitoneally administered along with some specific doses of atorvastatin.

KEY FINDINGS

Atorvastatin significantly reduced the hyperalgesia in diabetic rats. L-NAME pretreatment with atorvastatin showed the antihyperalgesic effect, suggesting the possible involvement of the NO pathway in atorvastatin protective action. Furthermore, co-administration of atorvastatin with AG and 7NI resulted in a significant increase in pain threshold in diabetic rats.

SIGNIFICANCE

Our results reveal that the atorvastatin protective effect on diabetic neuropathy is mediated at least in a part via the nitric oxide system.

Antihypernociceptive and Neuroprotective Effects of the Aqueous and Methanol Stem-Bark Extracts of Nauclea pobeguinii (Rubiaceae) on STZ-Induced Diabetic Neuropathic Pain

The greatest common and devastating complication of diabetes is painful neuropathy that can cause hyperalgesia and allodynia. It can disturb psychosocial functioning by increasing levels of anxiety and depression. This work was designed to evaluate the antihyperalgesic, antidepressant, and anxiolytic-like effects of the aqueous and methanol extracts of Nauclea pobeguinii stem-bark in diabetic neuropathy induced by streptozotocin in mice. Diabetic neuropathy was induced in mice by the intraperitoneal administration of 200 mg/kg streptozotocin (STZ) to provoke hyperglycemia. Nauclea pobeguinii aqueous and methanol extracts at the doses of 150 and 300 mg/kg were administered by oral route, and their effects were evaluated on antihyperalgesic activity (Von Frey filaments, hot plate, acetone, and formalin tests), blood glucose levels, body weight, serum, sciatic nerve proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and sciatic nerve growth factor (IGF and NGF) rates, depression (open field test, forced swimming test, tail suspension test), and anxiety (elevated plus maze, light-dark box test, social interaction). Oral administration of Nauclea pobeguinii stem-bark aqueous and methanol extracts (150 and 300 mg/kg) produced antihyperalgesic, antidepressant, and anxiolytic-like effects in STZ-induced diabetic neuropathic mice. Extracts also triggered a decrease in glycaemia and increased body weight in treated animals. They also significantly (p <0.001) reduced tumour necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-6 and significantly (p <0.001) increased nerve growth factor (NGF) and insulin-like growth factor (IGF) in sciatic nerves. The results of this study confirmed that Nauclea pobeguinii aqueous and methanol extracts possess antihyperalgesic, antidepressant, and anxiolytic activities and could be beneficial therapeutic agents.