Anticomplementary activity of boswellic acids--an inhibitor of C3-convertase of the classical complement pathway

3-Acetyl-11-keto-β-boswellic Acid-Based Hybrids Alleviate Acetaminophen-Induced Hepatotoxicity in HepG2 by the Regulation of Inflammatory and Oxidative Stress Pathways: An Integrated Approach

In an effort to develop new compounds for managing drug-induced liver injury, we prepared 23 novel hybrids based on 3-acetyl-11-keto-β-boswellic acid (AKBA) using various biocompatible linkers. A bioguided approach was employed to identify the most promising hybrid. Eight compounds exhibited superior anti-inflammatory activity compared to the parent compound. Two of these hybrids (5b and 18) were able to reduce gene expression of TNF-α in LPS-induced inflammation in RAW 264.7 cells, similar to dexamethasone. Subsequently, the hepatoprotective potential of these hybrids was evaluated against acetaminophen (APAP) toxicity in HepG2 cells at doses of 1 and 10 μM. Both hybrids effectively restored cytokine levels, which had been elevated by APAP, to normal levels. Furthermore, they normalized depleted superoxide dismutase and reduced glutathione levels while significantly reducing malondialdehyde (MDA) levels. Network pharmacology analysis suggested that AKBA-based hybrids exert their action by regulating PI3K and EGFR pathways, activating anti-inflammatory mechanisms, and initiating tissue repair and regeneration. Molecular docking studies provided insights into the interaction of the hybrids with PI3K. Additionally, the hybrids demonstrated good stability at different pH levels, following first-order kinetics, with relatively long half-lives, suggesting potential for absorption into circulation without significant degradation.

Bioavailability, anti-inflammatory and anti-arthritic effect of Acetyl Keto Boswellic acid and its combination with methotrexate in an arthritic animal model

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis is one of the most common disabling chronic progressive autoimmune diseases affecting the adult world population. Boswellia serrata has been a known anti-inflammatory agent since ancient times. Therefore, research on Boswellia extract based on Acetyl Keto Boswellic Acid (AKBA) content evaluating its efficacy and safety is necessary. The study aimed to find a suitable Boswellia extract rich in AKBA to evaluate its bioavailability, anti-inflammatory, and anti-arthritic effect. In addition, the synergistic action of AKBA extract with methotrexate (MTX) was also assessed on an animal model.

MATERIALS AND METHODS

Oral bioavailability of AKBA and the anti-inflammatory activity of 10% AKBA (5, 10, 20, 40 mg/kg b.w) was assessed and compared with 2% AKBA (40 mg/kg) and diclofenac (10 mg/kg). The effect of 10% AKBA at 20 mg/kg and 40 mg/kg was evaluated in the FCA induced arthritis animal model alone and combined with methotrexate (MTX) at 2 mg/kg b.w. Subplantar injection of FCA produced edema within a few hours with progressive arthritis by the 9th day after injection. All the treatments were initiated from the 10th day until the 45th day. Oral administration of 10% AKBA was done daily and MTX by intraperitoneal route once a week from day 10 to day 45. Paw volume, erythrocyte sedimentation rate (ESR), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP), total bilirubin, oxidative markers (superoxide dismutase (SOD) levels, malondialdehyde (MDA), total proteins and liver histopathology were examined.

RESULTS

10% AKBA provided 8.48-fold, 24.22-fold, 47.36-fold, and 110.53-fold higher AUC (0-α) of AKBA at 5 mg/kg, 10 mg/kg, 20 mg/kg and 40 mg/kg, respectively compared to 2% AKBA at 40 mg/kg. Percentage paw edema inhibition of 10% AKBA at 20 mg/kg and 40 mg/kg were significantly higher than 2% regular AKBA (40 mg/kg) and diclofenac (10 mg/kg). 10% AKBA at a dose of 20 and 40 mg/kg significantly reduced ESR compared with FCA treated group. A combination of methotrexate with 10% AKBA showed the highest reduction in ESR. 10% AKBA at both dose levels significantly reduced hepatic marker enzymes and total bilirubin levels. Treatment with 10% AKBA showed a significant increase in total proteins, antioxidant enzymes and a decrease in malondialdehyde levels. Similarly, 10% AKBA protected the hepatocytes compared with the FCA and FCA + MTX treated group. 10% AKBA was capable of significantly minimizing FCA and FCA + MTX induced changes.

CONCLUSION

Anti-inflammatory activity of AKBA due to inhibition of lipoxygenase (LOX) enzymes supports the use of AKBA in inflammatory disorders. Combination therapy of 10% AKBA with MTX is effective in inhibiting arthritis and circumventing hepatotoxicity produced by MTX in arthritic animals.

Immunomodulatory properties of triterpenes

The immune system is one of the main defence mechanisms of the human body. Inadequacy of this system or immunodeficiency results in increased risk of infections and tumours, whereas over-activation of the immune system causes allergic or autoimmune disorders. A well-balanced immune system is important for protection and for alleviation of these diseases. There is a growing interest to maintain a well-balanced immune system, especially after the Covid-19 pandemic. Many biological extracts, as well as natural products, have become popular due to their wide array of immunomodulatory effects and influence on the immune system. Triterpenes, one of the secondary metabolite groups of medicinal plants, exhibit immunomodulatory properties by various mechanisms. Different triterpenes, including components of commonly consumed plants, can promote some protection and alleviation of disease symptoms linked with immune responses and thus enhance overall well-being. This review aims to highlight the efficacy of triterpenes in light of the available literature evidence regarding the immunomodulatory properties of triterpenes. We have reviewed widely investigated immunomodulatory triterpenes; oleanolic acid, glycyrrhizin, glycyrrhetinic acid, pristimerin, ursolic acid, boswellic acid, celastrol, lupeol, betulin, betulinic acid, ganoderic acid, cucumarioside, and astragalosides which have important immunoregulatory properties. In spite of many preclinical and clinical trials were conducted on triterpenes related to their immunoregulatory actions, current studies have several limitations. Therefore, especially more clinical studies with optimal design is essential.

On Frankincense (Olibanum, Boswellia spp., Burseraceae)

Boswellia species (Burseraceae) are trees or shrubs whose area of distribution covers the wide geographic area between North Africa and India. After incision, their bark produces oleogum resin known as frankincense (Olibanum). In traditional medicine, frankincense is often used for medical treatment of arthritis, asthma, ulcerative colitis, coughs, sores, and wound healing. Various frankincense preparations are marketed almost exclusively as dietary supplements. Indian frankincense, or Olibanum indicum, is official in the European Pharmacopoeia. The major components of frankincense are boswellic acids, among which the most important and abundant is 3-O-acetyl-11-keto-b-boswellic acid (AKBA). AKBA is a 5-lipoxygenase inhibitor with anti-inflammatory and anti-arthritic effects. Besides, frankincense contains essential oil, whose composition greatly depends on the biological source, as well as arabinogalactans and glycoproteins. In small clinical trials, certain benefits of various frankincense preparations have been demonstrated in cases of ulcerative colitis, bronchial asthma, mild symptoms of irritable bowel syndrome, and various disorders of osteo-muscular system. However, for collagenous colitis and Crohn's disease remission maintenance, the evidence is ambiguous or negative. AKBA-containing extract was found advantageous in patients with osteoarthritis, and to some extent with rheumatoid arthritis. Almost all the trials had serious flaws in experimental design, such as insufficient sample size and/or incomplete reporting of data. For any clinical recommendation of frankincense preparations, larger and better-designed studies are needed.

Targeting complement cascade: an alternative strategy for COVID-19

The complement system is a stakeholder of the innate and adaptive immune system and has evolved as a crucial player of defense with multifaceted biological effects. Activation of three complement pathways leads to consecutive enzyme reactions resulting in complement components (C3 and C5), activation of mast cells and neutrophils by anaphylatoxins (C3a and C5a), the formation of membrane attack complex (MAC) and end up with opsonization. However, the dysregulation of complement cascade leads to unsolicited cytokine storm, inflammation, deterioration of alveolar lining cells, culminating in acquired respiratory destructive syndrome (ARDS). Similar pathogenesis is observed with the middle east respiratory syndrome (MERS), severe acquired respiratory syndrome (SARS), and SARS-CoV-2. Activation of the lectin pathway via mannose-binding lectin associated serine protease 2 (MASP2) is witnessed under discrete viral infections including COVID-19. Consequently, the spontaneous activation and deposits of complement components were traced in animal models and autopsy of COVID-19 patients. Pre-clinical and clinical studies evidence that the inhibition of complement components results in reduced complement deposits on target and non-target tissues, and aid in recovery from the pathological conditions of ARDS. Complement inhibitors (monoclonal antibody, protein, peptide, small molecules, etc.) exhibit great promise in blocking the activity of complement components and its downstream effects under various pathological conditions including SARS-CoV. Therefore, we hypothesize that targeting the potential complement inhibitors and complement cascade to counteract lung inflammation would be a better strategy to treat COVID-19.

Polyphenols from Blossoms of Citrus aurantium L. var. amara Engl. Show Significant Anti-Complement and Anti-Inflammatory Effects

Citrus aurantium L. var. amara Engl. (CAVA) was traditionally used as a digestant or expectorant in China. Crude polyphenols (CAVAP-W) extracted from blossoms of CAVA were mainly composed of eriocitrin/neoeriocitrin, eriocitrin/neoeriocitrin, rhoifolin, hesperidin, naringin, rutin, veronicastroside, neohesperidin, and hesperetin by LC-MS analysis. CAVAP-W showed significant anticomplement and anti-inflammatory effects. Due to the close relationship between anticomplement and anti-inflammatory activity, the anti-inflammatory effect was further investigated and the results showed that CAVAP-W significantly suppressed production of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and mRNA expression of inducible nitric oxide synthase (iNOS), IL-6, TNF-α, IL-1β, and cyclooxygenase-2 (COX-2) in lipopolysaccharides-stimulated RAW264.7 cells. Furthermore, CAVAP-W inhibited mitogen-activated protein kinase (MAPK) phosphorylation and NF-κB activation through suppressing nuclear translocation of nuclear factor-kappa B (NF-κB) P65, degradation and phosphorylation of IκBα, phosphorylation of IκKα/ß, c-Jun N-terminal kinase (JNK), and P38, and activation of COX-2, thereby exerting the anti-inflammatory effects.

Boswellic Acids and Their Role in Chronic Inflammatory Diseases

Boswellic acids, which are pentacyclic triterpenes belong to the active pharmacological compounds of the oleogum resin of different Boswellia species. In the resin, more than 12 different boswellic acids have been identified but only KBA and AKBA received significant pharmacological interest. Biological Activity: In an extract of the resin of Boswellia species multiple factors are responsible for the final outcome of a therapeutic effect, be it synergistic or antagonistic. Moreover, the anti-inflammatory actions of BAs are caused by different mechanisms of action. They include inhibition of leukotriene synthesis and to a less extend prostaglandin synthesis. Furthermore inhibition of the complement system at the level of conversion of C3 into C3_a and C3_b. A major target of BAs is the immune system. Here, BEs as well as BAs including KBA and AKBA, have been shown to decrease production of proinflammatory cytokines including IL-1, IL-2, IL-6, IFN-γ and TNF-α which finally are directed to destroy tissues such as cartilage, insulin producing cells, bronchial, intestinal and other tissues. NFĸB is considered to be the target of AKBA. The complex actions of BEs and BAs in inflamed areas may be completed by some effects that are localized behind the inflammatory process as such tissue destruction. In this case, in vitro- and animal studies have shown that BAs and BEs suppress proteolytic activity of cathepsin G, human leucocyte elastase, formation of oxygen radicals and lysosomal enzymes.

PHARMACOKINETICS

Whereas KBA is absorbed reaching blood levels being close to in vitro IC_50, AKBA which is more active in in vitro studies than KBA, but undergoes much less absorption than KBA. However, absorption of both is increased more than twice when taken together with a high-fat meal.Clinical Studies There are a variety of chronic inflammatory diseases which respond to treatment with extracts from the resin of Boswellia species. Though, the number of cases is small in related clinical studies, their results are convincing and supported by the preclinical data. These studies include rheumatoid arthritis, osteoarthritis, chronic colitis, ulcerative colitis, collagenous colitis, Crohn's disease and bronchial asthma. It can not be expected that there is cure from these diseases but at least improvement of symptoms in about 60-70 % of the cases. Side Effects The number and severity of side effects is extremely low. The most reported complaints are gastrointestinal symptoms. Allergic reactions are rare. And most authors report, that treatment with BEs is well tolerated and the registered side effects in BE- and placebo groups are similar.

Review of Anti-Inflammatory Herbal Medicines

Medicinal plants and their secondary metabolites are progressively used in the treatment of diseases as a complementary medicine. Inflammation is a pathologic condition that includes a wide range of diseases such as rheumatic and immune-mediated conditions, diabetes, cardiovascular accident, and etcetera. We introduce some herbs which their anti-inflammatory effects have been evaluated in clinical and experimental studies. Curcuma longa, Zingiber officinale, Rosmarinus officinalis, Borago officinalis, evening primrose, and Devil's claw are some of the introduced medicinal herbs in this review. Since the treatment of inflammation is not a one-dimensional remedy, this review tries to reach a multidimensional therapeutic approach to inflammation with the help of herbal medicine and modification in lifestyle.

What does complement do in Alzheimer's disease? Old molecules with new insights

Increasing evidence suggests that inflammatory and immune components in brain are important in Alzheimer's disease (AD) and anti-inflammatory and immunotherapeutic approaches may be amenable to AD treatment. It is known that complement activation occurs in the brain of patients with AD, and contributes to a local inflammatory state development which is correlated with cognitive impairment. In addition to the complement's critical role in the innate immune system recognizing and killing, or targeting for destruction, complement proteins can also interact with cell surface receptors to promote a local inflammatory response and contributes to the protection and healing of the host. On the other hand, complement activation also causes inflammation and cell damage as an essential immune function to eliminate cell debris and potentially toxic protein aggregates. It is the balance of these seemingly competing events that influences the ultimate state of neuronal function. Our mini review will be focusing on the unique molecular interactions happening in the AD development, the functional outcomes of those interactions, as well as the contribution of each element to AD.

Boswellic acids extract attenuates pulmonary fibrosis induced by bleomycin and oxidative stress from gamma irradiation in rats

BACKGROUND

Interstitial pulmonary fibrosis is characterized by an altered cellular composition of the alveolar region with excessive deposition of collagen. Lung inflammation is also common in pulmonary fibrosis. This study aims to test the inhibition of 5-lipooxygenase (5-LOX) by boswellic acid (BA) extract in an experimental model of pulmonary fibrosis using bleomycin (BL).

METHODS

Boswellic acid extract (1 g/kg) was force-fed to rats seven days prior to administration of BL or gamma irradiation or both. BL (0.15 U/rat) in 25 μl of 0.9% normal saline (NS) or 0.9% NS alone was administered intratracheally. Rats were exposed to two fractionated doses of gamma irradiation (0.5 Gy/dose/week) with a gamma cell-40 (Cesium-137 irradiation units, Canada) during the last two weeks of the experiment. BA was administered during BL or irradiation treatment or both. After the animals were sacrificed, bronchoalveolar lavage was performed; lungs were weighed and processed separately for biochemical and histological studies.

RESULTS

In rats treated with BL, levels of transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) were significantly elevated (P = 0.05 and P = 0.005). Hydroxyproline was highly and extensively expressed. Immunoreactive compounds were abundantly expressed, represented in the levels of macrophages infiltrate, accumulation of eosinophils and neutrophils in the lung as well as the aggregation of fibroblasts in the fibrotic area. The levels of lipoxygenase enzyme activity were significantly increased (P = 0.005). Antioxidant activities measured in BL-treated rats deteriorated, coupled with the elevation of both levels of plasma lipid peroxide (LP) content and bronchoalveolar lavage lactate dehydrogenase activity. BA-treated rats had reduced number of macrophages, (P = 0.01), neutrophils in bronchoalveolar lavage (P = 0.01) and protein (P = 0.0001). Moreover, the hydroxyproline content was significantly lowered in BA-treated rats (P = 0.005). BA extract inhibited the TGF-ß induced fibrosis (P = 0.01) and 5-LOX activity levels (P = 0.005).Histologically, BA reduced the number of infiltrating cells, ameliorated the destruction of lung architecture and attenuated lung fibrosis.

CONCLUSION

BA attenuates the BL-induced injury response in rats, such as collagen accumulation, airway dysfunction and injury. This study suggests that the blocking of 5-LOX may prevent the progression of fibrosis.

Modulation of the immune system by Boswellia serrata extracts and boswellic acids

Extracts from the gum resin of Boswellia serrata and some of is constituents including boswellic acids affect the immune system in different ways. Among the various boswellic acids 11-keto-beta-boswellic acid (KBA) and acetyl-11-keto-beta-boswellic acid have been observed to be active. However, also other boswellic acids may exhibit actions in the immune system. In the humoral defence system a mixture of boswellic acis at higher doses reduced primary antibody titres; on the other hand lower doses enhanced secondary antibody titres following treatment with sheep erythrocytes. In the cellular defence boswellic acides appear to increase lymphocyte proliferation whereas higher concentrations are even inhibitory. Moreover, BAs increase phagocytosis of macrophages. BAs affect the cellular defence system by interaction with production/release of cytokines. Thus, BAs inhibit activation of NFkappaB which is a product of neutrophile granulocytes. Consequently a down regulation of TNF-alpha and decrease of IL-1, IL-2, IL-4, IL-6 and IFN-gamma, which are proinflammatory cytokines by BEs and BAs has been reported. Suppressions of the classic way of the complement system was found to be due to inhibition of the conversion of C3 into C3a and C3b. However, which of these pharmacological actions contribute to the therapeutic effects and which is finally the best dosage of a standardized extract needs further examination. And it is also a question whether or not a single BA will have the same therapeutic effect as a standardized extract. Among the mediators of inflammatory reaction, mast cell stabilisation has been described by a BE. Inhibition of prostaglandin synthesis appears to play only a minor role as far as the anti-inflammatory effect is concerned. On the other hand the inhibitory action of BAs on 5-LO leading to a decreased production of leukotrienes has received high attention by the scientific community since a variety of chronic inflammatory diseases is associatied with increased leukotriene activity. At the end of the cascade of events in the cellular immune system as far as it directs to various tissues of the body - i.e. autoimmune diseases - formation of oxygen radicals and proteases (for example elastase) play an important destructive role. Here, BEs as well as BAs have been found to be inhibitory. From the pharmacological properties of BEs and BAs it is not surprising that positive effects of BEs in some chronic inflammatory diseases including rheumatoid arthritis, bronchial asthma, osteoarthritis, ulcerative colitis and Crohn's disease have been reported.

Prevention of colonic fibrosis by Boswellia and Scutellaria extracts in rats with colitis induced by 2,4,5-trinitrobenzene sulphonic acid

BACKGROUND

Currently, no effective preventive measures or medical therapies are available for intestinal fibrosis and, thus, surgery remains the only available strategy in the management of fibrostenotic enteropathies, especially Crohn's disease. The aim of this study was to evaluate the efficacy of a combined therapy of anti-inflammatory Boswellia and antifibrotic Scutellaria extracts on the development of colonic fibrosis in rats.

MATERIALS AND METHODS

Chronic colonic inflammation-associated fibrosis was induced in rats by intracolonic administration of 2,4,5-trinitrobenzene sulphonic acid (TNBS). Sixty-four healthy male Sprague-Dawley rats were assigned to five groups: 8 controls, 14 TNBS, 14 TNBS orally treated with Boswellia extracts (50 mg kg(-1) day(-1)), 14 TNBS orally treated with Scutellaria extracts (150 mg kg(-1) day(-1)), and 14 TNBS orally treated with both Boswellia (50 mg kg(-1) day(-1)) and Scutellaria extracts (150 mg kg(-1) day(-1)). The colon was removed after 21 days of treatment and assessed by macroscopic, histological, morphometric and immunohistochemical analyses. For immunohistochemical analysis, alpha-smooth muscle actin (alpha-SMA), collagen types I-III, connective tissue growth factor (CTGF), transforming growth factor-beta1 (TGF-beta1), Smad3, Smad7 and CD3 antibodies were used.

RESULTS

Combined oral administration of Boswellia and Scutellaria significantly improved the course and macroscopic findings of TNBS-induced chronic colitis assessed by disease activity index, colon weight, length, adhesions, strictures, dilatation, thickness, oedema, ulcerations and extension of damage. The histological severity of the colonic fibrosis was also notably improved by the treatment and associated with a significant reduction in the colonic expression of alpha-SMA, collagen I-III, CTGF, TGF-beta1, Smad3, and Smad7.

CONCLUSIONS

These data demonstrate that the prophylactic administration of anti-inflammatory Boswellia and antifibrotic Scutellaria extracts is effective in preventing colonic fibrosis in TNBS-induced colitis. Their antifibrotic mechanism of action seems to be mediated by the inhibition of TGF-beta1/Smad3 pathway.

Cytotoxic and apoptotic activities of novel amino analogues of boswellic acids

4-Amino analogues prepared from beta-boswellic acid and 11-keto-beta-boswellic acid, wherein the carboxyl group in ursane nucleus was replaced by an amino function via Curtius reaction, displayed improved cytotoxicity than the parent molecules. The same molecules also exhibited apoptotic activity by inducing DNA fragmentation.

Anisakis simplex: the activity of larval products on the complement system

The effects of the larval products (crude extract and excretory-secretory) of Anisakis simplex on the classical and alternative pathways of human complement system were investigated. This could constitute a mechanism to evade host defences, similarly than in other parasitic diseases. The larval products showed a stronger effect on the classical pathway than on the alternative pathway. The most pronounced modulating effects were found for the excretory-secretory products. Chelation of bivalent cations (Ca(2+) or Mg(2+)) by these larval products may be responsible for their mode of action on the alternative pathway, whereas the chelation is not likely to be particularly involved in the anticomplementary activity found on the classical pathway. Detailed studies revealed that the larval products of A. simplex act at the level of the C3 and other complement components. Heating the crude parasite extract led to a notable loss of haemolysis inhibition activity, and the addition of PMSF (a serine protease inhibitor) also cause variation in the activity of the crude extract.

Immunomodulatory role of Withania somnifera root powder on experimental induced inflammation: An in vivo and in vitro study

The aqueous suspension of Withania somnifera root powder was investigated for their in vivo and in vitro immunomodulatory properties. W. somnifera showed potent inhibitory activity towards the complement system, mitogen induced lymphocyte proliferation and delayed-type hypersensitivity reaction. Administration of W. somnifera root powder did not have a significant effect on humoral immune response in rats. Our results report immunosuppressive effect of W. somnifera root powder, thus it could be a candidate for developing as an immunosuppressive drug for the inflammatory diseases.

Acetyl-11-keto-beta-boswellic acid potentiates apoptosis, inhibits invasion, and abolishes osteoclastogenesis by suppressing NF-kappa B and NF-kappa B-regulated gene expression

Acetyl-11-keto-beta-boswellic acid (AKBA), a component of an Ayurvedic therapeutic plant Boswellia serrata, is a pentacyclic terpenoid active against a large number of inflammatory diseases, including cancer, arthritis, chronic colitis, ulcerative colitis, Crohn's disease, and bronchial asthma, but the mechanism is poorly understood. We found that AKBA potentiated the apoptosis induced by TNF and chemotherapeutic agents, suppressed TNF-induced invasion, and inhibited receptor activator of NF-kappaB ligand-induced osteoclastogenesis, all of which are known to require NF-kappaB activation. These observations corresponded with the down-regulation of the expression of NF-kappaB-regulated antiapoptotic, proliferative, and angiogenic gene products. As examined by DNA binding, AKBA suppressed both inducible and constitutive NF-kappaB activation in tumor cells. It also abrogated NF-kappaB activation induced by TNF, IL-1beta, okadaic acid, doxorubicin, LPS, H2O2, PMA, and cigarette smoke. AKBA did not directly affect the binding of NF-kappaB to the DNA but inhibited sequentially the TNF-induced activation of IkappaBalpha kinase (IKK), IkappaBalpha phosphorylation, IkappaBalpha ubiquitination, IkappaBalpha degradation, p65 phosphorylation, and p65 nuclear translocation. AKBA also did not directly modulate IKK activity but suppressed the activation of IKK through inhibition of Akt. Furthermore, AKBA inhibited the NF-kappaB-dependent reporter gene expression activated by TNFR type 1, TNFR-associated death domain protein, TNFR-associated factor 2, NF-kappaB-inducing kinase, and IKK, but not that activated by the p65 subunit of NF-kappaB. Overall, our results indicated that AKBA enhances apoptosis induced by cytokines and chemotherapeutic agents, inhibits invasion, and suppresses osteoclastogenesis through inhibition of NF-kappaB-regulated gene expression.

From traditional Ayurvedic medicine to modern medicine: identification of therapeutic targets for suppression of inflammation and cancer

Cancer is a hyperproliferative disorder that involves transformation, dysregulation of apoptosis, proliferation, invasion, angiogenesis and metastasis. Extensive research during the last 30 years has revealed much about the biology of cancer. Drugs used to treat most cancers are those that can block cell signalling, including growth factor signalling (e.g., epidermal growth factor); prostaglandin production (e.g., COX-2); inflammation (e.g., inflammatory cytokines: NF-kappaB, TNF, IL-1, IL-6, chemokines); drug resistance gene products (e.g., multi-drug resistance); cell cycle proteins (e.g., cyclin D1 and cyclin E); angiogenesis (e.g., vascular endothelial growth factor); invasion (e.g., matrix metalloproteinases); antiapoptosis (e.g., bcl-2, bcl-X(L), XIAP, survivin, FLIP); and cellular proliferation (e.g., c-myc, AP-1, growth factors). Numerous reports have suggested that Ayurvedic plants and their components mediate their effects by modulating several of these recently identified therapeutic targets. However, Ayurvedic medicine requires rediscovery in light of our current knowledge of allopathic (modern) medicine. The focus of this review is to elucidate the Ayurvedic concept of cancer, including its classification, causes, pathogenesis and prevention; surgical removal of tumours; herbal remedies; dietary modifications; and spiritual treatments.

Yin and Yang: complement activation and regulation in Alzheimer's disease

The spectrum of inflammatory diseases is nowadays considered to include diverse diseases of the central nervous system (CNS). Current evidence suggests that syndromes such as Alzheimer's disease (AD) have important inflammatory and immune components and may be amenable to treatment by anti-inflammatory and immunotherapeutic approaches. Compelling evidence has been reported that complement activation occurs in the brain with Alzheimer's disease, and that this contributes to the development of a local inflammatory state that is correlated with cognitive dysfunction. The complement system is a critical element of the innate immune system recognizing and killing, or targeting for destruction, otherwise pathogenic organisms. In addition to triggering the generation of a membranolytic complex, complement proteins interact with cell surface receptors to promote a local inflammatory response that contributes to the protection and healing of the host. Complement activation causes inflammation and cell damage, yet it is an essential component in trying to eliminate cell debris and potentially toxic protein aggregates. It is the balance of these seemingly competing events--the "Yin" and the "Yang"--that influences the ultimate state of neuronal function. Knowledge of the unique molecular interactions that occur in the development of Alzheimer's disease, the functional consequences of those interactions, and the proportional contribution of each element to this disorder, should facilitate the design of effective therapeutic strategies for this disease.

Synthesis and evaluation of potential complement inhibitory semisynthetic analogs of oleanolic acid

A number of semisynthetic analogs of oleanolic acid have been synthesized and tested for their complement inhibitory, cytotoxic and apoptotic activities. Among these, compounds 10 and 17 exhibited complement inhibitory potency superior to oleanolic acid. Both have also shown a moderate improvement in in vitro therapeutic index (T.I.).

Anticomplement activity of triterpenes from Crataeva nurvala stem bark in adjuvant arthritis in rats

Adjuvant arthritis is widely used as an experimental model for rheumatoid arthritis and inflammation. It is useful in the evaluation of anti-inflammatory drugs. Lupeol is a naturally occuring triterpene isolated from Crataeva nurvala stem bark, and its ester lupeol linoleate was synthesized. The effects of lupeol and lupeol linoleate on the development of complement in adjuvant arthritis in rats were studied and compared with those of indomethacin. The effect of lupeol linoleate in reducing the foot-pad thickness and complement activity in arthritic rats was even greater than that of unesterified lupeol and indomethacin. Because complement is highly involved in inflammation, the results suggest that the anti-inflammatory activity of triterpenes may be due to their anticomplementary activity.

Immunopotentiating compounds from Tinospora cordifolia

The active principles of Tinospora cordifolia a traditional Indian plant were found to possess anticomplementary and immunomodulatory activities. Syringin (TC-4) and cordiol (TC-7) inhibited the in vitro immunohaemolysis of antibody-coated sheep erythrocytes by guinea pig serum. The reduced immunohaemolysis was found to be due to inhibition of the C3-convertase of the classical complement pathway. However, higher concentrations showed constant inhibitory effects. The compounds also gave rise to significant increases in IgG antibodies in serum. Humoral and cell-mediated immunity were also dose-dependently enhanced. Macrophage activation was reported for cordioside (TC-2), cordiofolioside A (TC-5) and cordiol (TC-7) and this activation was more pronounced with increasing incubation times.

Effect of oleanolic acid on complement in adjuvant- and carrageenan-induced inflammation in rats

The present work was aimed at evaluating the influence of oleanolic acid on complement-related inflammation. In adjuvant-induced arthritis and carrageenan-induced paw oedema in rats, oleanolic acid was found to possess significant anti-inflammatory and complement-inhibitory activities. The intraperitoneal injection of oleanolic acid (60 mg kg-1, twice a day), before and after Freund's Complete Adjuvant challenge and thereafter repeated for several days, significantly reduced foot-pad thickness of experimental animal models and simultaneously reduced complement activity. Oleanolic acid also produced marked reduction in complement levels and inflammatory effects on carrageenan-induced paw oedema in rats when injected intraperitoneally (60 mg kg-1, twice a day).

Effect of a total extract from Fraxinus ornus stem bark and esculin on zymosan- and carrageenan-induced paw oedema in mice

This study investigates the total ethanol extract (TE) of the stem bark of Fraxinus ornus and its constituent esculin (EN). They inhibited classical pathway (CP) and alternative pathway (AP) of complement activation in mouse serum. After intraperitoneal administration the total extract displayed antiinflammatory activity in both zymosan- and carrageenan-induced paw oedema in mice. The results suggest that the traditional use of Fraxinus ornus stem bark extracts in the treatment of inflammatory disorders is at least partially due to its coumarin constituents.

Anti-complement activity of oleanolic acid: an inhibitor of C3-convertase of the classical complement pathway

Oleanolic acid is a naturally occurring compound, isolated from Luffa cylindrica, which inhibits the in-vitro immunohaemolysis of antibody-coated sheep erythrocytes by guinea-pig serum. In further experiments this reduced immunohaemolysis was found to be due to inhibition of the C3-convertase of the classical complement pathway. The threshold concentration for inhibition of C3-convertase was 100 micrograms mL-1. However, higher concentrations of oleanolic acid showed constant inhibitory effects on immunohaemolysis. Oleanolic acid also exhibited weak inhibitory effects on individual components of the complement system.