Ethnopharmacolological Potential And Medicinal Uses Of Hygrophila Auriculata
Hygrophila auriculata is belonging to family Acanthaceae and commonly known as “Neermulli in Tamil” is a common plant growing in marshy and water logged areas. It’s an important herbal plant, widely distributed in Sri Lanka and India, and is used for different medicinal purposes. Hygrophila auriculata (L. ) Nees, Acanthaceae, is a source of the Ayurveda drug; the aerial parts of the plant are acrid, bitter, aphrodisiac, tonic, sedative, used for blood disorders. The plant is known to possess antitumor, hypoglycemic, aphrodisiac, antibacterial, antioxidant and lipid peroxidation, hepatoprotective and hematopoietic activity. It contains lupeol, stigmasterol, butelin, fatty acids, and alkaloids. It is also used commercially as an ingredient of some over the counter (OTC) formulations in liver disorder and those prescribed by general tonic. Many constituents have been reported from the plant Hygrophila auriculata. In this review, discussed of pharmacological and medicinal properties of Hygrophila auriculata (Neermulli). Furthermore, need to done clinical investigation to promote as commercial drugs.
Introduction
Hygrophila or Marsh Barbel (English) it’s commonly used to call in Tamil as a Neermulli. It’s an annual herbal plant that grows up to the height of 60cms. The plant stem is square and hairy and thickened at the nodes. The bark is dark brown in color while the leaves are elliptic lanceolate and hispid. The flowers of this herb are violet and somewhat purple-blue. The fruit is oblong, linear, glabrous and about 1cm long containing seeds which are spherical hairy and brown in color.
Distribution: Around the world found in Sri Lanka, Myanmar, Indonesia, Malaysia and throughout the plains of India, in moist habitats such as marshy margins of canals and also found in tropical Himalaya.
Leaf: The leaf is dorsiventral, smooth and even with a fairly prominent midrib. The midrib is Plano convex in a sectional view with a flat ad axial side and a broad semicircular abaxial side. The midrib is 750μm along the median perpendicular plane and 1μm in the parallel. In the upper surface of a leaf, the epidermis is prominent with squares cells and a prominent cuticle. Beneath the epidermis there are about three layers of small collenchyma cells. Further below the collenchyma are four or five layers of wide thin walled parenchyma cells. The abaxial part of the midrib has an epidermis similar to the ad axial side. These may be one or two layers of collenchyma inner to the abaxial epidermis. The remaining ground tissue consists of wide, compact, thin walled parenchyma cells. The vascular bundle is single and elliptical in cross–section. It is 350μm horizontally and 150μm vertically. It consists of 8-10, parallel rows of xylem elements which are angular, thin walled and narrow. Phloem occurs as a thin sheath along the abaxial side of the xylem. In upper surface of a leaf there are two small, less prominent, circular accessory strands. They are circular with a cluster of xylem elements and a small nest of phloem elements.
Stem: The stem is roughly four angled in sectional view with a wide arenchymatous cortex and four angled stele. The epidermis is thin and less conspicuous. The outer cortex consists of four or five layers of radially aligned, small, compact squares parenchyma cells. This zone is uniformly 150μm wide. The inner cortex in much wider, about five rows wide and circular air chambers are formed by reticulate layers of narrow parenchyma cells. The stele has four semicircular thicker bundles located at four corners and two smaller bundles positioned opposite each other. The larger and smaller bundles are interlinked by a thin cylinder of small compact, dense xylem elements. The vascular bundles are collateral with dense xylem fibers, widely separated radial rows of xylem vessels and a thin arc of phloem. The pith is wide and parenchymatous while the pith cells are circular, less compact and thin walled.
Root: The root has an intact, continuous rhizodermis (epidermis) followed by two layers of tangentially oblong compact outer cortex. The inner cortex is wide and paerenchymatous. Wide, radially elongated air-chambers are formed by thin, uniserate partition filaments, made up of thin-walled parenchyma cells. Some of the partition cells have thick walls and are dilated and squarish rectangular. The vascular cylinder has a thin endodermal layer and a pericyclic layer. The xylem consists of five exarch strands and a few wide angular vessels in between the exarch strands. The phloem is in five small groups alternating with the primary xylem strands. The central part is narrow and parenchymatous.
Naturally, the herbal drugs contain many chemical compounds. Those compounds which are responsible for therapeutic effect is called as active constituents. There are number of examples or galenical preparations of the drugs differ to some extent from that of its active constituents of the crude drugs, which can enhance or retard the desired action. The use of isolated active constituents is obvious, since these compounds are having a fixed and definite physiological effect. There are so many active constituents still unknown. So the isolating and using the compounds in formulations will potentiate the activity. Isolation is a part of natural product chemistry, through which it is possible to separate different components and biologically active ones which can be incorporated as ingredients in the modern system of medicine. Column chromatography technique is widely used for the separation, isolation and purification of chemical constituents from natural drugs.
Review over pharmacological activities
Aphrodisiac activity: The ethanolic extract of aerial parts shows androgenic as well as improvement of sexual behavior of rat in dose dependent manner, it also improve the histo-architecture of testis and increase the concentration of sperm count in epididymis and also increase testosterone level. The effect of aerial parts of Hygrophila auriculata on the sexual behavior of male albino rats. The ethanolic extract of Hygrophila auriculata was directed to groups of rats in 100, 150 and 200 mg kg⁻¹ doses for a period of 28 days, and the action compared with control rats. The changes are organ weight, sexual behavior, histo-architecture and fructose levels of seminal vesicles were observed in body. The sexual behavior was assessed by determining parameters of aphrodisiac (mount frequency (MF), intromission latency, mount latency (ML) and post-ejaculatory latency). The ethanolic extract of Hygrophila auriculata showed that evident of anabolic effects in treated animals, as evidenced by gains in the body and reproductive organ weights. Hygrophila auriculata extracts were showed that able to raise the development of mature spermatozoa and witnessed in transverse section.
Liver protecting activity: The aqueous extract of whole plant and root of Hygrophila auriculata possesses hepatoprotective and antioxidative properties against CCl4- and paracetamol-induced hepatotoxicity’s. Petroleum ether extract of Hygrophila auriculataaffects liver and kidney functions and metabolism and hematological parameters in high doses (40 and 80 mg/kg) whereas low weekly dose (20 mg/kg) and low and moderate daily/therapeutic dose (2 and 4 mg/kg) does not exhibit any appreciable toxic action. Methanolic extracts of the aerial parts of show hepatoprotective activity against paracetamol and thioacetamide intoxification in rats. Ahmed et al. (2001) studied the against of aerial parts of against chemically induced hepatic carcinogenesis in Wistar rats. Methanol extract of seed presenting antitumor stimulating potential inhibit hepatic carcinogenesis in Wistar rats, increase GPx and CAT, ODC. Shivashangari et al. (2004) studied the protective efficacy of Hygrophila auriculata on acetaminophen-induced liver damage in rats. Shanmugasundaram & Venkataraman (2006) were studied about the aqueous extract of the roots for hepatoprotective in CCl4-induced liver toxicity in rats and in vitro antioxidant activity using ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. Shailajan et al. (2005) shown that has hepatoprotective activity of a semi liquid mixture of Hygrophila auriculata against CCl4 induced liver dysfunction in rats. Later they also reported that the slurry, aqueous extract and ethanolic extract of whole plant powder showed hepatoprotective effect against galactosamine induced hepatotoxicity.
Hypoglycemic activity: Ethanolic extract of aerial parts of Hygrophila auriculata (100 and 250 mg/kg body weight) when administered to rats for three weeks showed significant reduction in blood glucose level. There is also decrease in thiobarbituric acid reactive substances (TBARS) and hydro peroxide in both liver and kidney. The treatment with Al Eth significantly increased the glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST) and catalase (CAT) in the drug-treated group, which is comparable to the control group. This extracts also showed decreased lipid peroxidation that is associated with increased activity of superoxide dismutase (SOD) and catalase.
Fernando et al. (1991) investigated the effects of hot water extracts of Hygrophila auriculata whole plant material on the glucose tolerance of normal human subjects and maturity onset diabetic patients. Administration of aqueous extract of Hygrophila auriculata to rats prior to glucose loading showed hypoglycemic action as it was significant increase in the glycogen content of liver and muscle and a significant increase in triacylglycerol content of adipose tissue in comparison with control rats. However, there is no any effect on the gluconeogenic capacity of the kidney or intestinal glucose absorption.
Hematopoietic activity: Petroleum ether extract of root from Hygrophila auriculata increases WBC count significantly. Petroleum: ether and chloroform extracts of leaf showed hematopoietic activity as it significantly increases erythrocyte count, leukocyte count, and heamoglobin count.
Antioxidant activity: The methanolic extract of leaves contain phenolic and flavonoid shows promising antioxidant activity. Aqueous extract of leaves of A. longifolia shows potent antioxidant activity in various invitro model.
Neurology
a. Neurprotection: The terpenoid element of Hygrophila auriculata(100-200mg/kg) treated orally for seven days in rats then subject to transient global cerebral ischemia, supplementation was associated with improvements in cognitive testing and reductions in brain lipid peroxidation with a potency comparable to 500mg/kg Vitamin E.
b. Aphrodisiac: An ethanolic extract of the seeds (100-200mg/kg) administered to rats over 28 days caused dose-dependent increase in mounting frequency (380-472% of control) and similar reductions in mounting, intromission, and post-ejaculatory latencies; all doses were non significantly more libido enhancing than the active control of 0. 5mg/kg testosterone injections.
Cardiovascular Health
a. Blood: The chloroform extract of the leaf (250-500mg/kg intra peritoneal injections in mice) given for 22 days after cyclophosphamide-induced anemia was able to restore levels of blood cells shown that hematopoietic potential. The suppression in bone marrow cell count was also normalized by treatment with Hygrophila auriculata and elsewhere in haloperidol-induced anemic rats an ethanolic extract of this plant (100-200mg/kg) treated by intra peritoneal injections was able to almost normalize blood cell parameters (hematocrit, RBC count, hemoglobin) after 19 days. In rats aren’t feeble and assumed 200mg/kg of the ethanolic extract (injections), administration of the supplement does not appear to stimulate erythropoiesis and is met with a small (possibly clinically irrelevant) decline relative to untreated control.
Interactions with glucose metabolism
a. Absorption: A large oral dose of the water extract of the aerial parts of the plant (leaf and stem, dosed at 5g/kg bodyweight in rats) has failed to modify the absorption of glucose.
b. Glycogen: Oral ingestion of the water extract has failed to modify gluconeogenesis in the rat liver following an oral glucose tolerance test. In rats, administration of a water extract (at 5g/kg bodyweight) prior to glucose loading has resulted in increased glycogen storage in both the liver (108. 5+/-9. 5%) and skeletal muscle (57. 8+/-4. 2%) although an increase in triglyceride storage of adipose tissue (10. 2+/-1. 8%) was also noted.
c. Diabetes: 100-250mg/kg of the ethanolic leaf extract for three weeks in diabetic rats is able to reduce fasting blood glucose associated with a normalization of antioxidant enzymes (glutathione peroxidase, catalase, and glutathione-S-transferase) and lipid peroxidation. Oral ingestion of 10mL/kg of a hot water leaf extract (where each mL is equivalent to 1g of plant material) in normal humans is able to reduce exposure to glucose following an oral glucose tolerance test by 25%; the drink was slightly more effective in diabetics since it reduced exposure by 36%.
Interactions with cancer metabolism
Hepatocarcinoma: A methanolic extract of the seeds (200-400mg/kg) every other day for eight weeks in rats given hepatic tumors appears to be able to reduce subsequent foci development by up to 51% (relative to control) associated with an attenuation of the toxin-induced decline in glutathione peroxidase and catalase.
Discussion and conclusion
With the advent of modern scientific methods many of the medicinally important plants came under chemical scrutiny, leading to the isolation of active principles. Soon after their isolation and characterization, these compounds either in pure state or in the form of well-characterized extracts become part of pharmacology. At present the study on medicinal plant is one of the important areas of biomedical research. By and large the pharmacological activity of a medicinal plant Hygrophila auriculata (K. Schum) possess various biological activities, ranging from analgesic, antitumor, antioxidant, hepatoprotective, hypoglycemic, haematinic, diuretics, free radical scavenging, anthelmintic, anti-inflammatory, antipyretic, anabolic. androgenic properties, antimicrobial, antibiotic, insecticidal and hormonal properties, to highly important pharmacological and pharmaceutical activities. It is interesting to note that the earlier scientific investigations of this plant, Hygrophila auriculata (K. Schum). Mostly, the pharmacological studies have been performed in vitro and in vivo with animals. Therefore, clinical studies are urgently needed in order to confirm traditional applications using rational phytotherapy and the qualitative analysis along with the quantitative estimation of these components hence forms the basis of the drug development from natural medicinal sources.
