BAYABAS

Guava Tree

Family Name:       Myrtaceae (2)

Scientific name:  Psydium guajava linn. (2)

Common name:  Bayabas , Guayaba , Guava (2)

Guava is a shrub or small tree up to 7 m high, sparsely branched. It has aromatic leaves, opposite, entire, 4-8 cm long, with prominent veins on the underside, resembling ribs. White attractive flowers, grouping from 1 to 3; numerous stamens arranged on a width disk. The guava fruit is fleshy, variable in shape and size depending on the variety.  (1)

PARTS USED

Fruits:

The fruit, exuding a strong, sweet, musky odor when ripe, may be round, ovoid, or pear-shaped, with 4 or 5 protruding floral remnants (sepals) at the apex; and thin, light-yellow skin, frequently blushed with pink. The central pulp, slightly darker in tone, is juicy and normally filled with very hard, yellowish seeds, though some rare types have soft, chewable seeds. Actual seed counts have ranged from 112 to 535 but some guavas are seedless or nearly so. (3)

Guava Fruits

Leaves and flowers:

The leaves are aromatic when crushed, are evergreen, opposite, short-petiole, oval or oblong-elliptic, somewhat irregular in outline, leathery, with conspicuous parallel veins, and more or less downy on the underside. Faintly fragrant, the white flowers, borne singly or in small clusters in the leaf axis, with 4 or 5 white petals which are quickly shed, and a prominent tuft of perhaps 250 white stamens tipped with pale-yellow anthers. (3)

 Guava Leaves and Flowers

Guava bark

Barks:

The bark is a smooth, thin, copper-colored that flakes off, showing the greenish layer beneath; and also the attractive, "bony" aspect of its trunk which may in time attain a diameter of 10 in (25 cm). Young twigs are quadrangular and downy. (3) 

                          ACTIVE CONSTITUENTS

• Guava is rich in tannins, phenols, triterpenes, flavonoids, essential oils, saponins, carotenoids, lectins, vitamins, fiber and fatty acids. (4) (5) 
• Guava fruit is higher in vitamin C than citrus (80 mg of vitamin C in 100 g of fruit) and contains appreciable amounts of vitamin A as well. (4) (5) 
•  Guava fruits are also a good source of pectin - a dietary fiber. (4) (5) 
• The leaves of guava are rich in flavonoids, in particular, quercetin. Much of guava's therapeutic activity is attributed to these flavonoids. The flavonoids have demonstrated antibacterial activity. (4) (5) 
•  Quercetin is thought to contribute to the anti-diarrhea effect of guava; it is able to relax intestinal smooth muscle and inhibit bowel contractions. In addition, other flavonoids and triterpenes in guava leaves show antispasmodic activity.  (4) (5) 
• Guava also has antioxidant properties which is attributed to the polyphenols found in the leaves. (4) (5) 
• Chloroform-methanol extracted lipids of guava seeds was 9.1% on a dry weight basis. Analysis yielded 12 fatty acids, with a pattern similar to cottonseed oil. Protein content of seeds was 9.73% on a dry weight basis. (6)

TRADITIONAL USE

• Guava leaves are used in folk medicine as a remedy for diarrhea and, as well as the bark, for their supposed antimicrobial properties and as an astringent. Guava leaves or barks are used in traditional treatments against diabetes
•  In Trinidad, a tea made from young leaves is used for diarrhea, dysentery and fever.
• In Jamaica guava is used traditionally for diarrhea and for bathing wounds. Similar use is made of guava in the rest of the Caribbean, where the leaves and buds are used for diarrhea, dysentery and stomach aches.
•  In Ghana, guava is also used for stomach problems and diarrhea and the leaves are chewed for toothache.
• In the Canary Islands guava is used for vomiting and nausea as well as for diarrhea.
•  In South America, the leaves and bark of the guava tree are used to treat dysentery and diarrhea. It is also used for vaginal discharges and menstrual pain and as a gargle for sore throats.  It can be applied externally for skin ulcers and vaginal irritation. Guava is also beneficial for colds and coughs.
• Similar uses are made of guava in the Philippines; it is also used to reduce uterine hemorrhaging. The leaves are rolled up and placed into the nostrils to stop nosebleeds.

Traditional Preparation: The fruit and juice is freely consumed for its great taste, nutritional benefit and nutrient content, as well as an effective children's diarrhea remedy. The leaves are prepared in a standard decoction and dosages are generally 1 cup 1-3 times daily. (15)

PHARMACOLOGICAL  ACTIVITY

Diarrhea

Guava leaf extracts decreased spasms associated with induced diarrhea in rodents. Reduced defecation, severity of diarrhea, and intestinal fluid secretion reductions have also been demonstrated. Activity is generally associated with the ability of quercetin and its derivatives to affect smooth muscle fibers via calcium antagonism, inhibit intestinal movement, and reduce capillary permeability in the abdominal cavity. (8) (9)

Clinical data

In vitro studies suggest leaf and bark extracts are bactericidal against a range of pathogens causative of diarrhea; however, data from controlled clinical trials are limited, and few of the trials have been published in peer-reviewed journals. Trials have evaluated guava leaf extract in infantile viral enteritis, infectious gastroenteritis and acute diarrhea with improvement in outcome measures including number of daily stools, time to cessation, stool composition, and abdominal pain and spasms for P. guava -treated patients. (10)

Microbicidal / Antidiiarrheal

 Microbicidal effect of medicinal plant extracts (Psidium guajava Linn. and Carica papaya Linn.) upon bacteria isolated from fish muscle and known to induce diarrhea in children: Study concludes that guava sprout extracts is a feasible treatment option for diarrhea caused by E coli or S aureus-produced toxins, with quick curative effect, easy availability and low cost. (7)  

Cardiovascular effects

In an animal model, a water-alcohol extract of P. guajava depressed guinea pig atrial contractility in a concentration-dependent manner. The negative inotropic effect of the extract was blocked by atropine sulfate. In hypertensive rats, intravenous administration of guava leaf aqueous extracts produced a dose-dependent reduction in systemic arterial blood pressure and heart rate The effect of guava leaf extract on isolated vascular smooth muscle and aortic rings has also been evaluated. (11)

Clinical data

The addition of 400 mg to 1 kg daily of guava fruit for up to 12 weeks resulted in decreased systolic and diastolic blood pressure in several clinical studies. (10)

Hypolipidemic effects

Hypolipidemic activity has been demonstrated in rats administered raw fruit peel.(13)

Clinical data

Limited evidence from a few clinical trials suggests that the addition of guava fruit or guava leaf tea to the diet can improve the lipid profile. Trials were conducted over a range of doses (0.4 to 1 kg/day) and duration from 4 to 12 weeks. (10)

Diabetes

Extracts of guava bark, leaves, and fruit containing tannins, flavonoids, triterpenes, and quercetin have been evaluated in induced-diabetic rats. In some, but not all, experiments, no effect was observed in either normal rats or normal glucose-loaded rats. A polyphenolic effect may be responsible for the observed inhibition of low-density lipoprotein glycation Inhibition of protein tyrosine phosphatase 1B  as well as increased glucose uptake in rat hepatocytes has also been described. (14)

Clinical data

Limited evidence from a few clinical trials suggests guava fruit and leaf tea extracts may be of benefit in type 2 diabetes. Reductions in postprandial serum glucose levels of a lesser size than chlorpropamide and metformin have been demonstrated, and inhibition of alpha-glucosidase enzymes has been suggested to play a role in the mechanism of action.(8)

Dysmenorrhea

An in vitro study using uterine tissue from rats demonstrated a spasmolytic effect of guava leaf extract. Activity is postulated to be due to an estrogenic effect of the flavonoids or to anti-inflammatory effects. (11)

Clinical data

Decreases in dysmenorrheal pain intensity were reported after 4 months of daily guava leaf extract standardized at 6 mg of flavonoid content per day. (8)

Anti epileptic

Study evaluated the anti epileptic activity of a leaves extract of P. guajava in seizure induced by maximal electroshock and pantaloon territorialize. Results showed the leaves extract at higher and medium doses produced highly significant and sustained increases in onset of convulsions and decrease in rate of convulsion. Activity may be due to presence of flavonoids and saponins. (12)

Antioxidant

Aqueous extracts from P. guajava have antioxidant or radical-scavenging activity. Most of the activity is associated with the polyphenols; however, the guava extracts also contain antioxidants, such as ascorbic acid and carotenoids. (16) A study done to determine the effects of guava consumption on antioxidant status and lipid profile in normal male youth showed a significant increase in level of total antioxidants and reduced oxidative stress and also increase the level of HDL cholesterol significantly.  (17)

Anti-Ulcer

Study showed rats pretreated with P guajava extract from fresh tender leaves showed antiulcer activity in aspirin-induced gastric ulcer model with a significant reduction of ulcer index, pepsin activity, free and total acidity, volume and mucus content of gastric juice. (18)

Antihyperglycemic

Thr Unripe Fruit Peel: Study evaluated the glycemic potential of an aqueous extract of unripe fruit peel in STZ-induced diabetic rats. Results showed normal, mild, and severely diabetic rat models had hypoglycemic and antidiabetic effect. (19)

TOXICITY

Acute toxicity tests in rats and mice have found the median lethal dose of guava leaf extracts to be more than 5 g/kg. In vitro genotoxicity and mutagenicity tests on P. guajava in human peripheral blood lymphocytes found no disturbances in cell division or hemolysis

Despite experiments suggesting hepatoprotective effects intraperitoneal administration of ethanolic leaf extracts in rats has resulted in increases in serum liver enzymes, an effect that may be dose dependent. No histological evidence of hepatotoxicity has been observed. (20) (21)

REFERENCES:

Pharmacognosy Topics-medicinal plants. http://www.medicinalplants-pharmacognosy.com/herbs-medicinal-plants/guava/
(1)

Philippine medicinal plants. http://www.stuartxchange.com/Bayabas.html 
(2)

Morton, J. 1987. Guava. p. 356–363. In: Fruits of warm climates. Julia F. Morton, Miami, FL. https://www.hort.purdue.edu/newcrop/morton/guava.html#Description
(3)

Ashutosh Chaturvedi. Psidium guajava A fruit or medicine-an overview pp.63-67 http://www.academia.edu/5430956/Psidium_guajava_A_Fruit_or_Medicine_-_An_Overview
(4)

Narendra Vyas, Mukul Tailang,Narayan Prasad Gavatia,Bhaskar K. Gupta. ANTIOXIDANT POTENTIAL OF PSIDIUM GUAJAVA LINN. http://sphinxsai.com/sphinxsaivol_2no.1/pharmtech_vol_2no.1/PharmTech_Vol_2No.1PDF/PT=65%20417-419).pdf

(5)

Electroanalytical studies on the corrosion inhibition behavior of guava (Psidium guajava) leaves extract on mild steel in hydrochloric acid / K. K. Anupama, Joseph Abraham / Research on Chemical Intermediates December 2012
(6)

Anti-proliferative activity of essential oil extracted from Thai medicinal plants on KB and P388 cell lines / Cancer Letters, Vol 235, Issue 1, Pages 114-120 / J. Manosroi, P. Dhumtanom, A. Manosroi 
(7)

Gutiérrez RM, Mitchell S, Solis RV. Psidium guajava : a review of its traditional uses, phytochemistry and pharmacology. J Ethnopharmacol . 2008;117(1):1-27.
(8)

Zhang WJ , Chen BT , Wang CY , Zhu QH , Mo ZX . Mechanism of quercetin as an antidiarrheal agent [in Chinese]. Di Yi Jun Yi Da Xue Xue Bao . 2003;23(10):1029-1031. 
(9)

Singh RB , Rastogi SS , Singh R , Ghosh S , Niaz MA . Effects of guava intake on serum total and high-density lipoprotein cholesterol levels and on systemic blood pressure . Am J Cardiol . 1992;70(15):1287-1291. 
(10)

Chiwororo WD, Ojewole JA. Biphasic effect of Psidium guajava Linn.(Myrtaceae) leaf aqueous extract on rat isolated vascular smooth muscles. J Smooth Muscle Res . 2008;44(6):217-229. 
(11)


Evaluation of Anti Epileptic Activity of Psidium Guajava Leaves Extract in Mice / Sushma. M*, Eswarudu. MM, Venkateshwaralu. G and Radhika. P / International Journal of Research in Pharmaceutical and Biomedical Sciences, Vol. 3 (2) Apr – Jun2012 
(12)

Rai PK, Mehta S, Watal G. Hypolipidaemic & hepatoprotective effects of Psidium guajava raw fruit peel in experimental diabetes. Indian J Med Res . 2010;131:820-824.  

(13)

Cheng FC, Shen SC, Wu JS. Effect of guava ( Psidium guajava L.) leaf extract on glucose uptake in rat hepatocytes. J Food Sci . 2009;74(5):H132-H138.
(14)

Abba, Kakuwa. Jaherbs 2011-2012. http://www.jaherbs.com/index.php?option=com_content&view=article&id=45&Itemid=27
(15)

Jimenez-Escrig A , Rincon M , Pulido R , Saura-Calixto F . Guava fruit ( Psidium guajava L.) as a new source of antioxidant dietary fiber . J Agric Food Chem . 2001;49(11):5489-5493. 
(16)

Intestinal anti-spasmodic effect of a phytodrug of Psidium guajava folia in the treatment of acute diarrheic disease / Xavier Lozoya et al / Journal of Ethnopharmacology • Volume 83, Issues 1-2, November 2002, Pages 19-24 
(17)

THE EFFECTS OF GUAVA (PSIDIUM GUAJAVA) CONSUMPTION ON TOTAL ANTIOXIDANT AND LIPID PROFILE IN NORMAL MALE YOUTH / Asmah Rahmat et al / AJFAND • Vol 6 No 2, 2006 
(18)

Effect of Psidium guajava Linn. leaf extract on liver cells / Chanchal K Roy*, Amit Kumar Das / NSHM Journal of Pharmacy and Healthcare Management, Vol. 02, February (2011) pp. 83-88 
(19)

Jaiarj P , Khoohaswan P , Wongkrajang Y , et al. Anticough and antimicrobial activities of Psidium guajava Linn. leaf extract . J Ethnopharmacol . 1999;67(2):203-212.
(20)

Sambo N, Garba SH, Timothy H. Effect of the aqueous extract of Psidium guajava on erythromycin-induced liver damage in rats. Niger J Physiol Sci . 2009;24(2):171-176. 
(21)

Compiled by: Maria Sheena G. Campaner