A review on efficacy of Cissus quadrangularis in pharmacological mechanisms

Cissus quadrangularis a succulent vine belongs to Vitaceae family is widely distributed throughout tropical and subtropical regions of the world and used frequently to various disorders. The plant has been reported to contain fl avonoids, triterpenoids, phytosterols, glycosides and rich source of calcium. This study aims to bring a systematic review of C. quadrangularis in various pharmacological mechanisms. Evidence from the previous studies suggested the effi cacy of C. quadrangularis with antimicrobial, anti-diabetic, anti-infl ammatory, anti-obesity, anti-oxidant, bone turnover, cardiovascular and hepatoprotective activities. In conclusion, Cissus quadrangularis appears worthy of pharmacological investigations for new drug formulations.


Introduction
Cissus quadrangularis is a tendril-climbing shrub with stout, leshy quadrangular stems. The leaf portion constitutes only 5% -8% of the aerial plant parts; the leshy, green stem is the major portion. The plant is widely distributed throughout tropical and subtropical regions of the world such as India, Sri Lanka, South Africa, Thailand, Java and Philippines. The entire parts (root, stem, and leaves) of the plant have been cited in both Ayurvedic and Unani systems for its medicinal values. Due to its bone ligation properties, the plant is referred to as 'Asthisamharaka' in Sanskrit. C. quadrangularis belonging to Vitaceae family is one of the most widely used for the treatment of piles, anorexia, indigestion, chronic ulcers, asthma, otorrhoea, wounds and in augmenting fracture healing process [1][2][3]. The stout quadrangular stem is traditionally used for treatment of bone fracture, piles, chronic ulcers, asthma, scurvy, irregular menstruation, constipation and blindness.
The major constituents found in the plant are ascorbic acid, carotene A, ketosteroid, calcium, triterpenoids. It has been reported to contain three unsymmetric tetracyclic triterpenoids along with β-sitosterol, β-amyrin, and β-amyrone. In addition, it also contains lavonoids, phytosterols, δ-amyrin, δ-amyron, resveratrol, piceatannol, pallidol, parthenocissine, quadragularins and water-soluble glycosides [4][5][6][7][8]. The unique chemical constituents of Cissus -novel lavonoids and indanes, as well as phytosterols and ketosteroids-have shown promise as powerful and ef icient antioxidants. The plant is reported to contain inorganic minerals like calcium, iron, copper, zinc and potassium. Though the plant is used to treat various ailments over the years there is a lack of systematic review and meta-analysis of the medicinal use of this plant. This study aims to ill this gap through a systematic review of clinical evidence to determine the ef icacy of C. quadrangularis.

Sources and methodology
The search was done in electronic databases of PubMed, Scopus, ScienceDirect, Web of Science and Google Scholar for studies using the key terms: Cissus quadrangularis, antimicrobial, anti-obesity, anti-in lammatory, bone resorption and antioxidant. The inclusion was based reported articles on pharmacological activities of C. quadrangularis which are discussed in detail. All the data were extracted and explained in respective subheadings.

Antimicrobial activity
Chloroform extract of C. quadrangularis L. was reported to exhibit Helicobactericidal activity under in vitro conditions [9]. In one study [10], the ethyl acetate extract and methanol extract of both fresh and dry stems of C. quadrangularis exhibited antimicrobial activity against Gram-positive bacteria, including Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Streptococcus species. Copper oxide nanoparticles (CuO NPs) synthesized using C. quadrangularis acts as better fungicidal agent against Aspergillus niger and Aspergillus lavus as reported earlier [11]. Similarly, silver chloride nanoparticles synthesized using leaf extract of C. quadrangularis exhibited better antibacterial activity against Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli and Proteus vulgaris than tetracycline [12]. C. quadrangularis mediated calcium oxide nanoparticles showed maximum inhibition on E. coli [13]. The minimum inhibitory concentration was about 7.8 μg for Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa followed by 15.6 μg for Salmonella typhi, Shigella dysenteriae and Vibrio cholerae.
Methanolic extracts of aerial parts of C. quadrangularis were tested for in vitro anthelmintic activity against Haemonchus contortus, the causative agent of Haemonchosis, is a nematode parasite that feeds on blood of small ruminant animals and causes anaemia, anorexia, reduced growth, and eventual death of host animals [14]. The extract produced a dose dependent anthelmintic activity in both adult motility assay and egg hatch inhibition assay. Further, C. quadrangularis induced 88% egg hatching inhibitory effect at 1 mg/ml concentration. Cysteine protease from C. quadrangularis showed zone of inhibition of 21 and 20 mm against Bacillus cereus and Bacillus megaterium respectively at 4.74 U ml -1 [15]. In another study, methanolic extract of C. quadrangularis was explored for antiviral activity against HSV type1 and 2 and Vero cells. Both HSV1 and HSV2 showed more sensitivity at 1: 400 dilution [16].

Anti-diabetic activity
Lekshmi, et al. [17,18] suggested the anti-diabetic potential of C. quadrangularis stem extract, mediated through the modulation of the antioxidant defence system. The ethyl acetate fraction is rich in quercetin supplementation of the plant might be bene icial as a food supplement for the attenuation of diabetic complications. Further, antidiabetic activity of the plant is associated with potentiating the antioxidant defense system and suppressing in lammatory responses.

Anti-infl ammatory activity
Panthong, et al. [19] revealed the anti-in lammatory effect of C. quadrangularis which is associated with luteolin, and by β-sitosterol. Likewise, methanolic root extract of C. quadrangularis showed potent activity of 4.16 at 50 mg/ kg dose level [20]. Ethyl acetate extract of C. quadrangularis potently inhibited lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophage cells in a dosedependent manner [21]. The mRNA and protein expressions of inducible nitric oxide synthase were suppressed also by the extract as was p65 NF-κB nuclear translocation. Further study demonstrated that the extract by itself induced heme oxygenase-1 gene expression at the protein and mRNA levels in dose-and time-dependent manner. Similarly, acetone extract of the plant showed cycloxygenase and 5-lipoxygenase inhibition with IC50 values of 7 μg/ml, 0.4 μg/ml, and 20 μg/ ml for cycloxygenase-1, cycloxygenas-2 and 5-lipoxygenase respectively. It also showed anti-in lammatory activity on RAW 264.7 cell line with IC50 value 65 μg/ml. In addition to this, the extract exhibited inhibition of proin lammatory mediators like inducible nitric oxide synthase and TNFα, along with translocation of nuclear factor E2 p45-related factor 2 and upregulation of Heme oxygenase-1 [22]. Administration of C. quadrangularis extract signi icantly attenuated the gastric lesions induced by aspirin and this was accompanied by the rise in uric acid, antioxidative enzymes, SH groups, and a signi icant decrease in lipid peroxidase, TNF-alpha, myeloperoxidase and xanthine oxidase activities [23]. Kanwar, et al. [24] con irmed the anti-in lammatory and cartilageregenerative properties of C. quadrangularis and its mode of action via the inhibition of matrix metalloproteinase and reactive oxygen species. Hydroalcoholic extract of the plant treatment also reduced serum TNF-α level, oxidative stress and synovial expression of in lammatory and angiogenesis marker [25].

Anti-obesity activity
Aqueous leaf and stem extract of C. quandrangularis at 300 mg dose was effective in reducing body fat as well as improving blood parameters associated with metabolic syndrome [26]. Similarly, it was effective in reducing weight, improving blood parameters associated with metabolic syndrome, as well as serotonin levels in obese and overweight individuals [27]. Ross [28] reported that effectiveness of C. quandrangularis in the management of obesity and complications associated with metabolic syndrome. The plant also demonstrated ef icacy in the control and lowering of triglyceride, total cholesterol, low-density lipoprotein cholesterol, and fasting blood glucose levels [29]. C. quadrangularis inhibited lipid accumulation without showing cytotoxicity to 3T3-L1 adipocytes [30]. Further, it decreased adipogenesis/lipogenesis-related mRNA expression levels of fatty acid binding protein, fatty acid synthase, lipoprotein lipase, stearoyl-CoA desaturase-1, and acetyl-CoA carboxylase. The results suggested that the plant have an anti-obesity effect by its ability to decrease expression levels of adipogenesis/lipogenesis-related genes and proteins.

Anti-oxidant activity
Ethanolic extract of C. quadrangularis exhibited signi icant scavenging effect on DPPH free radical, superoxide radical, hydroxyl radical production, and inhibition of lipid peroxide production in erythrocytes [31]. Further, the extract upregulates superoxide dismutase, glutathione peroxidase and endothelial nitric oxide synthase expression in hydrogen peroxide-injured human ECV304 cells [32]. Extracts of C. quadrangularis signi icantly and dose-dependently increased the latency to clonic and generalized tonic-clonic seizures and decreased the number and duration of seizures. Anticonvulsant activities of the plant are accompanied by its anxiolytics effects which are supported by its antioxidant properties and mediated [33]. C. quadrangularis being rich in antioxidants such as vitamin C and lavonoids was studied for its effect on the antioxidant system of femur in ovariectomized rats by Muthusami, et al. [34]. The extract prevented ovariectomy induced oxidative stress in the femur.
Bone Turnover activity C. quadrangularis was tested for its bone protective properties and studied to discern the mechanism by which it is bene icial to bone [35]. It had protected the microarchitecture of the long bones from ovariectomy-induced bone loss because of decreased in lammation and modulation through the bone morphogenetic protein and Wingless-related integration site (Wnt) signaling pathways. The results indicated that the plant is a potential therapeutic agent to treat postmenopausal osteoporosis with no side effects. Petroleum ether extract of C. quadrangularis signi icantly increased the thickness of both cortical and trabecular bone suggesting the strong anti-osteoporotic activity of the plant. In addition, the extract reduced bone loss, as evidenced by the weight gain in femur, and also reduced the osteoclastic activity there by facilitating bone formation [36,37]. Also, percentage of the total length of ossi ied cartilage (bone) in pups were higher suggesting that maternal administration of C. quadrangularis petroleum ether extract during pregnancy can stimulate the development of fetal bone growth during the intra-uterine developmental period [38]. In another study, ethanol extract showed signi icant restorative progress with mineralization along with fairly well distributed osteocytes as well as complete recovery with essential features of normal bone [39].
Tasadduq, et al. [40] examined the effectiveness of C. quadrangularis in promoting osteoblast differentiation of the murine pre-osteoblast cell lines. The ethanolic extract augmented osteoblast differentiation, as re lected by a substantial increase in expression of the early osteoblast marker alkaline phosphatase activity. Osteogenic potential of Cissus was studied by Toor, et al. [41] and ethanolic extract of the plant accelerated fracture healing as well as early remodeling of fracture callus. The authors also studied the effect of hexane and dichloromethane fraction on the differentiation and mineralization of mouse pre-osteoblast cell line [42].
C. quadrangularis treatment has increased the DNA synthesis of human osteoblastic SaOS-2 cells indicating increased proliferation of these cells [43]. The study also revealed that the anabolic actions of ethanolic extract of C. quadrangularis in human osteoblast like cells are mediated through increased mRNA and protein expression of Runx2, a key transcription factor involved in the regulation of bone matrix protein. Osteogenic potential of C. quadrangularis on the mandibular fracture healing was studied by and the plant helps in reducing pain, swelling, and fracture mobility and accelerate the healing of fracture jaw bones [44,45].

Cardiovascular activity
In a study by Oben, et al. [46], C. quandrangularis brought about signi icant reductions in weight and blood glucose levels, while decreasing serum lipids thus improving cardiovascular risk factors.

Hepatoprotective activity
Swamy, et al. [47] investigated the hepatoprotective activity of methanol extract of C. quadrangularis against rifampicin-induced hepatotoxicity in rats. It was concluded that the mechanism of hepatoprotection may be attributed to its antioxidant activity especially the presence of β-carotene. The plant affords hepatoprotection by its antioxidant and insulin-sensitizing activities [48]. It also showed antilipid peroxidative, free-radical scavenging property and ameliorated the liver damage by an increase in antioxidant enzymes activities [23].

Conclusion
Evidence from the previous studies suggested the ef icacy of C. quadrangularis in treating various ailments. The major pharmacological activities of the plant include antimicrobial, anti-diabetic, anti-in lammatory, anti-obesity, anti-oxidant, bone turnover, cardiovascular and hepatoprotective. Further, the most extensive clinical studies using standardized extracts of Cissus alone or in combination with other ingredients involve weight loss and the regulation of blood glucose and lipids. Thus, Cissus quadrangularis appears worthy of pharmacological investigations for new drug formulations.