Phytopharmacological overview of Psidium guajava Linn .

Psidium guajava Linn. possesses useful medicinal benefits. It has been recognized as the medicinally essential phytoconstituents, such as phenolic, flavonoid and carotenoid. Numerous pharmacological investigation have confirmed that the ability of this plant is to exhibit antimicrobial, antidiabetic, cardioprotective, neuroprotective, hepatoprotective, antioxidant and anticancer activities and it supports the traditional uses. This is a comprehensive of the phytoconstituents and pharmacological benefits.


ANTIMICROBIAL ACTIVITY
P. guajava leaf extract (2 and 5 g/kg) reduced the occurrence of cough induced by capsaicin aerosol by 35 and 54%, respectively, within 10 min after injection of the extract. The growth of Staphylococcus aureus and beta-streptococcus group A, is inhibited by aqueous, methanol and chloroform extract of dry P. guajava leaves. Therefore P. guajava leaf extract may be recommended for cough. 22 Vieira et al 23 have reported the antibacterial effect of P. guajava leaves extracts and found that they inhibited the growth of the S. aureus. The methanolic plant leaf extracts of P. guajava and barks of this plant have antimicrobial activity. The organism inhibited is Salmonella species, Bacillus species, and the concentrations vary according to the organisms. 24 The microbicidial activity of P. guajava is attributable to guajaverine and to psydiolic acid. The active flavonoid compound guaijaverin extracted from the leaves of the same plant is reported to have high potential antiplaque activity. 25 The in vitro antibacterial activity of P. guajava leaf extracts of S. aureus is possibly due to protein degrading activity of the extracts. 26 P. guajava leaves flavonoids are also shown to have bacteriostatic effects on fish pathogenic bacteria. 27 P. guajava and Azadirachta indica extracts showed higher antimicrobial activity food borne pathogens of Gram-positive bacteria than Gram-negative bacteria (except for Vibrio parahaemolyticus, Pseudomonas aeroginosa, and Acromonas hydrophila. 28 The γ-terpinene and γ-pinene obtained by hydro distillation showed antimicrobial activity against Propionibacterium acnes. 29 Minimum inhibitory concentration is found in the methanolic (625 ug/ml) and aqueous (7.5 mg/ml) leaf extracts of P. guajava and minimum bactericidal concentration recorded for methanolic (1.25 mg/ml) and aqueous extracts (12.5 mg/ml) against multidrug resistant clinical isolates of S. aureus strains. Human RBC based haemolytic assay showed absence of haemolysis and this confirms its safety. 30 The essential oil from leaf extract of P. guajava exhibited the inhibitory activity towards S. aureus and Salmonella species. 31 Pelegrini et al 32 isolated the peptide Pg-AMP1 from the seeds of P. guajava. Pg-AMP1 showed growth reduction in Klebsiella sp. and Proteus sp. The recombinant Pg-AMP1 peptide showed inhibitory activity against Escherichia coli, K. pneumonia, P. aeruginosa, S. aureus, and S. epidermides bacteria. 33 Metwally et al 18 isolated five flavanoids from P. guajava leaves and found that good antimicrobial activity of the extracts, as well as the isolated compounds. Crude aqueous mixture and water soluble methanol extract from leaf and bark of P. guajava showed strong antibacterial activity against multidrug-resistant V. cholera. 34 The decoction of P. guajava showed antibacterial activity against Shigella flexneri and V. cholerae. It reduced the production of cholera toxin and labile toxin as well as their binding to ganglioside monosialic acid. 35 Mao et al 36 purified and concentrated total saponin from P. guajava leaf. It interferes with the envelope subunit gp41 form the critical 6-HB structure, thus inhibit the entry of HIV into target cells. Dhiman et al 37 found that methanolic extract of P. guajava leaf has bacteriostatic and fungistatic in action. P. guajava tea showed efficient control of epidemic and pandemic influenza viruses, including oseltamivir-resistant strains, and its broad target blockage makes it less likely to lead to the emergence of viral resistance. 38 P. guajava might be valuable sources for the synthesis of new antibacterial agents against Helicobacter pylori. 39 Methanolic and ethanolic extract of P. guajava leaf showed antimicrobial activities against E. coli and Salmonella enteritidis. 40 Acetone-water extract of P. guajava have catechin and it may be showed antimicrobial, anti-inflammatory and analgesic properties. 41 From these results, P. guajava extracts may contribute the novel antibiotics from natural resources. Lutterodt 42 isolated quercetin and quercetin-3-arabinoside, from P. guajava leaf. The leaf extract has a morphine-like inhibition of the release of acetylcholine in the coaxially stimulated ileum, with an initial increase, followed by a gradual decrease of muscular tone. Quercetin inhibited intestinal contraction induced by different concentrations of calcium. The ileum is being more sensitive to quercetin. These calcium-antagonist properties of quercetin explain the spasmolytic effect of this popular herbal remedy. 43 Lozoya et al 44 suggested that the aglycone quercetin in P. guajava leaf may be responsible for spasmolytic activity.

ANTI-INFLAMMATORY ACTIVITY
Ethyl acetate extract of P. guajava suppressed the interferon gama (IFN-γ)/TNF-α-co-induced production of thymus and activation-regulated chemokine protein and mRNA in HaCaT cells. It also inhibited the TNF-α/IFN-γ-co-induced activation of STAT1 and NF-κB as well as increased the expression of mRNA and heme oxygenase-1 protein. This demonstrates that P. guajava inhibits expression of chemokine in keratinocytes by inducing heme oxygenase-1 expression and it highlight the therapeutic uses of P. guajava in atopic dermatitis and inflammatory skin diseases. 45 Ethanolic extract of P. guajava leaf significantly inhibited lipopolysaccharide induced production of nitric oxide and prostaglandin E2 in a concentration-dependent manner. P. guajava extract suppressed the expression and activity of inducible nitric oxide synthase and cyclooxygenase-2 through the downregulation of ERK1/2 activation in RAW264.7 macrophages. It also exhibited significant anti-inflammatory activity in 2 different animal models. 46 Ethyl acetate of P. guajava reduced antigen, induced the release of β-hexosaminidase and histamine in IgE-sensitized RBL-2H3 cells. It also inhibited expression of IL-4 and TNF-α mRNA and protein production. It suppressed antigen-induced COX-2 mRNA and protein expression in these cells, as well as antigen-induced activation of NFAT and reactive oxygen species (ROS). Moreover, it inhibited antigen-induced activation of NF-κB and degradation of IκB-α. P. guajava extract suppressed antigen-induced phosphorylation of Syk, LAT, Gab2, and PLCγ2 but not Lyn, and inhibited antigen-induced phosphorylation of downstream signaling intermediates including MAP kinases and Akt. 47 Matsuzaki et al 48 isolated benzophenone and flavonol galloyl glycosides from 80% MeOH extract of P. guajava together with five known quercetin glycosides. These compounds showed significant inhibitory activities against histamine release from rat peritoneal mast cells, and nitric oxide production from a murine macrophage-like cell line.

ANTIOXIDANT ACTIVITY
Ethanolic and aqueous leaf extract of P. guajava contain high total phenolic content (575.3 ± 5.5 and 511.6 ± 6.2 mg of gallic acid equivalent/g, respectively). The higher the sample concentration used, the stronger is the free radical-scavenging effect. 49 Akinola et al 50 suggested that ethanolic leaf extract of P. guajava possesses the beneficial effect on gossypol-induced sperm toxicity, and hence it may enhance male fertility due to rich natural antioxidants in it. The total flavonoids are primarily identified in the aqueous and ethanolic leaf extracts of P. guajava which may possess the potential antioxidative activities. 51 The ethanolic extracts of the leaves of P. guajava possess beneficial effects on sperm production and quality, and may thus improve the sperm parameters of infertile males with oligospermia and nonobstructive azoospermia. 52 Shabana et al 53 isolated quercetin and two quercetin glycosides (avicularin and guaijaverin) from P. guajava and have urease inhibitory activity. Free radical scavenging activity of the P. guajava leaves harvested during May and August are high, and have higher amounts of acetic acid, 3-hydroxybutyric acid, glutamic acid, citric acid, malonic acid, trans-aconitic acid, ascorbic acid, maleic acid, cis-aconitic acid, protocatechuic acid, asparagine, xanthine, and epicatechin than the leaves harvested during October and December. Epicatechin and protocatechuic acid seems to have enhanced, free radical scavenging activity of the P. guajava leaves. 54 Methanolic extract of P. guajava contains the highest amount of total phenolics (380.08 ± 4.40 mg/L gallic acid equivalents), P. guajava contains high amount of total flavonoids (269.72 ± 2.78 microg/mL) among 10 Nigerian plants. Percentage 2,2-Diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity (82.79 ± 2.84%) and reductive potentials (0.79 ± 0.04) also higher P. guajava. 55 Nantitanon and Okonogi 56 isolated quercetin, morin, and quercetin-3-O-glucopyranoside from leaf of P. guajava. Quercetin possess free radical scavenging activity approximately four times higher than morin and two times higher than quercetin-3-O-glucopyranoside. The reducing power of quercetin is eight times higher than morin and two times higher than quercetin-3-O-glucopyranoside. This confirmed that quercetin is the more active antioxidant from guava leaves. Phorbol myristate acetate and the DPPH radical scavenging assay for the spray dried extracts of P. guajava presented significant antioxidant activity in a dose-dependent manner and showed no toxicity to the human neurtophils. 57 The antioxidant activities of different solvents of P. guajava leaves (water, ethanol, methanol, and various concentrations of hydroethanol) have demonstrated that the antioxidant ability of P. guajava leaf extracts have a strong relationship with phenolic compound when compared to flavonoid content. 58 Aqueous extract of P. guajava and its synthesized TiO 2 nanoparticls are found to possess maximum antioxidant activity and antimicrobial activity when compared with ascorbic acid. 59 Recently, four new compounds, guavinoside C, D, E and F are isolated from the leaves of P. guajava and these compounds showed antioxidant activities in DPPH, 2,2'-azino-bis-3-ethyl benzthiazoline-6-sulphonic acid (ABTS) and ferric reducing antioxidant potential (FRAP) assays. 60 Roasted P. guajava seeds showed higher DPPH radical scavenging and reducing power activities. 61 These results indicate that P. guajava could be a suitable source of natural antioxidants. The ethanolic extract of P. guajava has been found to show Antioxidant activity in all the tests done like DPPH assay, reducing power assay, nitric oxide scavenging assay, H 2 O 2 radical scavenging assay and SO radical scavenging assay. 62 The Antioxidant activity when evaluated in diabetic mice induced with streptozoin showed the decrease in level of glucose and lipid peroxides when treated with the ethanolic leaf extract of P. guajava. 63

ANTIDIABETIC ACTIVITY
Treatment with guava juice (1 g/kg) produced a noticeable hypoglycemic action in normal and alloxan-induced diabetic mice. 64 Aqueous leaf extract of P. guajava (250 mg/kg), showed statistically significant hypo-glycemic activity. 65 Intraperitoneal injection of P. guajava leaf extract (10 mg/kg) exhibited a significant inhibitory effect on protein tyrosine phosphatase1B in 1-and 3-month-old Lepr(db)/Lepr(db) mice. The butanol-soluble fraction significantly decrease the number of lipid droplets. 66 Ethanolic extract of stem bark of P. guajava exhibited significant hypoglycaemic activity in alloxan-induced hyperglycaemic rats. 67 The aqueous leaf extract of P. guajava have the potential effect of inhibition of the alpha-glucosidase activity from the small intestinal mucosa of diabetic mouse. 68 P. guajava bud extract has significant insulin-mimetic and potentiating activity. Noni leaf, noni, fruit commercial noni juice and mangrove bean have insulin-like activity with minimum effect on insulin action. Habitual intake of P. guajava and noni is proposed to offer better protection against type 2 diabetes mellitus. 69 Shen et al 70 investigated the effect of aqueous and ethanolic leaf extracts of P. guajava on hypoglycemia and glucose metabolism in streptozotocin induced type 2 diabetic rats. The acute and long-term feeding of the aqueous and ethanolic extract of P. guajava leaves have significantly decreased in the blood sugar level and increased the plasma insulin level. The activities of hepatic hexokinase and glucose-6-phosphate dehydrogenase is observed in diabetic rats fed with aqueous as well as ethanolic extracts and increased phosphofructokinase activity only in aqueous extract. Unripe fruit peel aqueous extract guava has shown hypoglycaemic as well as antidiabetic effect in normal, mild and severely diabetic rats induced by streptozotocin. 71 Cheng et al 72 identified and suggested that quercetin in the aqueous extract of P. guajava leaves promotes the uptake of glucose in rat clone 9 hepatocytes, which may contribute to the alleviation of hypoglycemia in diabetes. Fructosamine and glycated hemoglobin are significantly reduced in ethyl acetate fraction of P. guajava leaf treated groups. It also improved the antioxidant potential by decreasing lipid peroxidation (LPO) and increasing in the activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and reduced glutathione (GR). 73 Huang et al 74 suggested that P. guajava fruit (125 and 250 mg/kg) protected pancreatic tissues, against lipid peroxidation (LPO) and DNA strand breaks in streptozotocin induced diabetic rats. It also noticeably inhibited pancreatic expression of NF-kB protein and restored the activities of SOD, CAT and GPx. Dipeptidyl-peptidase IV is an important enzyme which maintains blood glucose homeostasis. The ethanolic P. guajava and its components flavonol-glycoside inhibit dipeptidyl-peptidase IV in a dose-dependent manner. 75 Ethanolic leaves extract of P. guajava showed a significant reduction in blood glucose and glycated hemoglobin levels as well as increase in plasma insulin levels in streptozotocin induced diabetic rats. It also restored the activities of carbohydrate metabolizing enzymes. 76 Treatment with P. guajava leaf extracts promoted the expression of IRS-1, AKT, PI3Kp85 and IRS-1, AMKP, and AKT308, phosphorylation, accompanied by increasing the ratios of the membrane to the total expression of glucose transporter 4 and adiponectin receptor 1 transcription in the skeletal muscles. 77 These supports the modulating effect of P. guajava leaf extracts in insulin-related signaling. The poly formulation of Anacardium occidentale, Eucalyptus globulus, P. guajava, and Xylopia aethiopica extracts yielded significant result as well as reduces some other complications associated with diabetes in alloxaninduced diabetic models. 78 Recently, aqueous extract of P. guajava leaves (250 and 500 mg/kg/d) re-set the raised circulating levels of leptin, insulin, and hepatic glucose transporter expression to promote insulin resistance, dyslipidemia, and hypertension in high fructose intake male rats. 79

HEPATOPROTECTIVE ACTIVITY
Aqueous leaf extracts of P. guajava at 250 mg/kg and 500 mg/kg, significantly reduced the levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and bilirubin. The higher dose of P. guajava extract guarded the increase in liver weight, whereas the lower dose of P. guajava extract is ineffective except in the paracetamol induced liver damage. In the chronic liver injury induced by CCl 4 , the higher dose of P. guajava leaf extract is found to be more effective than the lower dose. 80 In the acute liver damage induced by different hepatotoxins, methanolic, ethyl acetate and aqueous leaf extract of P. guajava (200 mg/kg, p.o.) significantly reduced the elevated serum levels of AST, ALT, ALP and bilirubin in CCl 4 and paracetamol induced hepatotoxicity. Methanolic extract of leaves of P. guajava possesses better hepatoprotective activity compared to other extracts. Histological examinations of liver tissues also support the hepatoprotection. 81 Pretreatment with aqueous extract of P. guajava leaf possesses, hepatoprotective property at lower dose (150 mg/kg) against erythromycin-induced liver damage and a hepatotoxic property at higher dose (300 and 450 mg/kg) and recommended further studies with prolonged duration. Rai et al 82 evaluated the hypolipidaemic and hepatoprotective effects of unripe P. guajava fruit peel aqueous extract in streptozotocin induced severely diabetic rats. The extract has significant hepatoprotective and hypolipidaemic activity in addition to its antidiabetic activity.

CARDIOPROTECTIVE AND HYPOTENSIVE ACTIVITY
Aqueous-alcohol extract of P. guajava dry leaves depress the atrial contractility of guinea pig, in a dose-dependent fashion. The compound is concentrated using glacial acetic acid after removing the less polar fractions (acetone, chloroform, hexane, ethanol and methanol). The acetic acid fraction (10-800 mg/l) of P. guajava reduced myocardial force, increased the atrial relaxation time measured, abolished the positive staircase effect in a dose-dependent fashion suggesting a decrease of the cellular inward calcium current and its inotropic effect is abolished by cholinergic receptor blockade, indicating a cholinergic involvement in the mechanism of action of the extract. These data support that the extract of P. guajava leaves depress myocardial inotropism. 83 Acute intravenous administrations of the aqueous extract of P. guajava leaf (50-800 mg/kg) produced a concentration-dependent, significant reduction in systemic arterial blood pressures and heart rates of hypertensive rats. The numerous phytoconstituents such as, polyphenolic compounds, flavonoids, pentacyclic triterpenoids, quercetin, guiajaverin, tannins, and other chemical compounds present in the plant are considered for the observed hypotensive effects of the plant leaf extract. 84 Belemtougri et al 85 evaluated P. guajava and Diospyros mespiliformis (crude decoction, aqueous and ethanolic extracts) for their antagonistic activities on caffeine induced release of calcium from the sarcoplasmic reticulum of skeletal muscle in rats. These different extracts have shown a decrease of caffeine induced calcium release in a dose-dependent manner. P. guajava leaf extracts are more active than D. mespiliformis and crude decoctions have shown better inhibitory activity. Aqueous leaf extract of P. guajava produced dose-dependent (0.25-2 mg/ ml contracted aorta rings. The effect is then assessed in the presence of phentolamine and nifedipine. The sensitivity of the aortic rings to collective doses of P. guajava is significantly improved in the presence of phentolamine. These data suggest that the effect of P. guajava is either by activation of alpha-adrenoceptor or acting via a calcium ion channel. 86 Quercetin and gallic acid is one of the major antioxidative bioactive compounds of P. guajava and Limonium wrightii, respectively. 87 The extracts P. guajava and L. wrightii significantly attenuated ischemic contracture during ischemia and also enhanced myocardial dysfunction after reperfusion. Increases in malondialdehyde (MDA) and decreases in high-energy phosphates in the reperfused hearts are significantly lessened with the both plant extracts. Quercetin and gallic acid also exerted the same beneficial effects. These results indicate that P. guajava and L. wrightii have cardioprotective effects against myocardial ischemia-reperfusion injury in isolated rat hearts, primarily through their radical-scavenging actions.
Recently, the administration of the leaves extracts of P. guajava significantly reduced the blood glucose, fructosamine and glycated hemoglobin levels. Cardiac isoform of liver alpha 2 macroglobulin which is the major protein correlated with earlier stages of cardiac hypertrophy. This protein level is decreased significantly in extract treated groups and these findings support the benefits of extract for preventing cardiovascular complications associated with diabetes. 88

ANTICANCER ACTIVITY
Research based on anticancer drug from natural compounds enabled the discovery of several drugs presently used in cancer therapy. P. guajava extracts modified the balance of Th1/Th2 to a dominant status of Th1 by directly reducing regulatory activity T cell. In pretreated mice exhibited retarded growth of s.c. inoculated B16 melanoma cells. 89 P. guajava leaf oil showed the highest anti-proliferative activity with (4.37 times more potent than vincristine) than other 16 Thai medicinal platnsin P388 cell line. 90 The aqueous extract of P. guajava inhibited the cancer cell DU-145 in a dose-and time-dependent manner. TUNEL assay and flow cytometric analysis confirmed the cell cycle arrests at G0/G1 phase. Additionally, suppression of the matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9), and the upregulation of active caspase-3 in DU-145 are also effected in a dose-dependent manner, implicating a potent anti-metastasis power of P. guajava. 91 P. guajava have huge amounts of soluble polyphenolics including gallic acid, catechin, epicatechin, quercetin, and rutin and to exhibit potent anticancer activity. 92 Treatment with P. guajava arrests the cell cycle at G0/G1 phase with huge amount of apoptotic LNCaP cells. It also significantly diminished both the prostate specific antigen serum levels and tumor size in a xenograft mouse tumor model and is a promising antiandrogen-sensitive prostate cancer agent. 93 Park et al 94 isolated a sesquiterpene (β-caryophyllene oxide) from the essential oils of P. guajava, Origanum vulgare, Cinnamomum sp, Eugenia caryophyllata and Piper nigrum. β-caryophyllene oxide inhibited the constitutive activation of PI3K/AKT/ mammalian target of rapamycin/ ribosomal p70 S6 signaling pathways; and also caused the activation of ERK, JNK, and p38 mitogen-activated protein kinase in tumor cells. It also down-regulated the expression of various downstream gene products that mediate cell proliferation, survival, metastasis, angiogenesis, and increased the expression of p53 and p21. Aqueous soluble polyphenolic fraction of P. guajava leaves effectively inhibited the expressions of VEGF, IL-6 and IL-8 cytokines, as well as MMP-2 and MMP-9. Simultaneously, it activated tissue inhibitor of metalloproteinases (TIMP-2) and suppressed the cell migration and the angiogenesis. P. guajava potentially possesses a strong anti-DU145 effect. 95 Hexane fraction of P. guajava is the most powerful inducer of cytotoxic and apoptotic effects in PC-3 cells. It suppresses the AKT/mammalian target of rapamycin/ribosomal p70 S6 kinase and mitogen-activated protein kinase signaling pathways and this correlated with down-regulation of various proteins that mediate cell proliferation, cell survival, metastasis, as well as angiogenesis. 20 The P. guajava extract exerted anticancer activity on haematological and solid neoplasias. P. guajava and its pulp ex-tract are found to induce the apoptosis, which accompanied by caspase activation and p16, p21, Fas ligand, Bcl-2-associated agonist of cell death as well as TNF receptor super-family, member 10b, over expression. 96 The ethanolic leaf extract of P. guajava showed inhibition (61.3%) against the proliferation of colon cancer cell line SW480. 21 The P. guajava extracts contains the meroterpenes guajadial, psidial A and psiguadial A and B. Both in vitro (nine human cancerlines) and in vivo (Solid Ehrlich murine breast adenocarcinoma model) showed to have highly effective anticancer property. The ability of the meroterpene-enriched fraction to reduce tumor growth and stimulate uterus proliferation, suggest that these compounds may act as Selective Estrogen Receptors Modulators. 97 Kim et al 98 also isolated β-caryophyllene oxide from the essential oils of P. guajava and O. vulgare. β-caryophyllene oxide suppressed constitutive STAT3 activation in multiple myeloma, prostate cancer and breast cancer cell lines. The suppression is mediated via the inhibition of activation of upstream kinases c-Src and JAK1/2. The inhibition of STAT3 activation subsequently inhibited the proliferation of cell, stimulated apoptosis and abrogated the invasive potential of tumor cells. Overall, all these findings suggest that P. guajava leaves can interfere with various signaling pathways linked with tumorigenesis and provide a source of possible therapeutic compounds for cancer prevention and treatment.

NEPHROPROTECTIVE ACTIVITY
The aqueous extract of P. guajava fruits have more quercetin, myricetin, and caffeic acid and ethanolic extract have more ferulic acids, cinnamic acids, and coumaric acid. 99 Aqueous and ethanloic extract intake at 2 %, significantly reduced glucose, blood urea nitrogen levels, and increased insulin level in plasma of diabetic mice. Both extracts, dose-dependently reserved glutathione content, retained activity of CAT and GPx, and decreased ROS, IL-6, TNF-α and interleukin-1β (IL-1β) levels in the kidney. It also significantly declined renal N (ε)-(carboxymethyl)lysine, pentosidine and fructose levels, and suppressed renal activity of aldose reductase. These findings support that guava fruit could protect the kidney against diabetic progression. 99 Triterpenoids isolated from P. guajava leaves. 100 The level of fasting blood glucose is increased and the insulin and insulin sensitivity index are decreased in the model group when compared with normal control in streptozotocin induced diabetic rats. The levels of blood urea nitrogen and creatinine are increased with histopathological changes related to diabetic nephropathy in the kidney, which are the glomerular endothelium and mesangial cell proliferation, capillary narrowed, the base-membrane incrassation, glomerular swelling, cysts narrowed and tubules edema. Triterpenoids can decrease the level of blood glucose, blood urea nitrogen and creatinine levels in diabetic rat effectively, increase the insulin sensitivity index and protect renal lesions in diabetic rats. 100

CONCLUSION
Various researches on the medicinal use of plant extract is must in the modern era as many chemically synthesized drugs are highly effective in causing many adverse effects in the humans. The phytochemical and pharmacological investigations carried out on P. guajava validate the immense potential of this plant in the treatment of numerous diseases. Additional researches are needed for the compound isolation and identification for the product development from P. guajava for the future generations. Every medicinal property of many medicinal plants are also to be determined.