Synthesis and Characterization of Carbon Dots from Guava Leaves (Psidium guajava L.): UV Blocking, Antioxidant and Antimicrobial Functions

The aim of this research is to know about if the guava (Psidium guajava L.) leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages indicate a positive test as contraception antifertility to white mice (Rattus norvegicus). The sample is guava leaf from Mungkid, Magelang Central of Java Indonesia. The animals experiment are the white mice on 140-300 g for female, 200-250 g for male and about 3 months of age in average. The steps of this research are : (1) preparing sample, i.e. washing, drying on to indirect sunlight and make the sample into powder, (2) isolation the guava leaf powder in soxhlet instrument with hexane, (3) evaporation the sample with rotary evaporator until guava leaf hexane extract produced, (4) maseration the sample with methanol, (5) evaporation the sample with rotary evaporator until guava leaf methanol extract produced, (6) conducting contraception antifertility activity test to guave leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages to mice white. The results of this research are guava leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages indicate a negative contraception antifertility test to white mice but in these dossages have indicated that an antiimplantation effect (the total natality of fetus is less than the total implantation site in mice white). Keywords: Guava leaf, contraseption antifertility, methanol extract, white mice, implantation

Effect of guava leaves on growth and the non-specific immune response of Penaeus monodon

Streptococcus pyogenes is a bacterium that can cause various diseases such as pharyngitis and other diseases. Some antibiotics for these bacteria such as tetracycline and erythromycin have high resistance rates. Empirically, guava leaf (Psidium guajava Linn) is widely used as an herbal medicine to cope with various diseases. Active compounds such as flavonoids, tannins, saponins, and alkaloids contained in that guava leaf have antibacterial effects. This research aims to determine the anti bacterial power of guava methanol extract (Psidium guajava Linn) on the growth of Streptococcus pyogenes. The research was done by experimental method, and the sample was from culture of Streptococcus pyogenes. The test material was in the form of methanol extract of guava leaf (Psidium guajava Linn) at 100% concentration with positive control that is bacitracin. The antibacterial power test was performed by the Kirby-Bauer diffusion method in Mueller-Hinton Agar, microdilution broth method and confirmation with streak which was performed four times. The antibacterial power results showed the formation of the drag zone at 100% concentration, as well as on the streak that has been performed dilution test showed the absence of colony at 50% concentration. The presence of antibacterial power due to guava leaf (Psidium guajava Linn) contains active substances namely flavonoids, tannins, saponins and alkaloids that can inhibit bacterial growth. The conclusion of this research is the methanol extract of guava leaf (Psidium guajava Linn) has antibacterial power against Streptococcus pyogenes.

Enhancement of functional and sensory properties of eastern prickly pear (Opuntia humifusa) by fermentation with yuza peel and guava leaf

The characteristics of bioactive compounds from guava (Psidium guajava L.) leaf extract, their biological activity, and their technological applications are critical topics in many engineering fields. Guava leaf extract is rich in bioactive compounds, including phenolic acids, flavonoids, tannins, terpenes, alkaloids, etc. Bioactive compounds from guava leaf exhibit notable synergistic effects in enzyme inhibition, as well as antimicrobial and anti-inflammatory activities. Natural bioactive compounds are complicated due to their sensitivity and instability during storage, but their use is promising. Thus, for bioactive compound protection, advanced techniques such as the encapsulation, microemulsion, and nanosuspension of such natural bioactive compounds can be a promising approach. These methods are particularly important for the development of natural preservatives serving as additive agents, which have significant industrial relevance. However, sufficient scientific evidence is required to make a health claim on and to promote the functional benefits of guava leaf extract. This review focuses on recent research into guava leaf extract and its technical roles. Demonstrations of the chemical structure of bioactive compounds are addressed, besides discussing their analytical methods, nutritional bioavailability, biological activity, and synergy effects. Furthermore, this review study considers the methods used to protect the active compounds and technological applications in food, pharmaceuticals, and cosmetic products.

. Literature review Activity on Guava Leaf Extract (Psidium guajava L.) as an antioxidant Using to DPPH Method (Supervised by Faradiba and Aminah). Guava leaf (Psidium guajava L.) is one of the plants having the potential as an antioxidant. Antioxidants can donate their electrons which allow to inhibit, prevent or scavenge the reactions of free radicals and oxidants. The research aimed to determine the highest antioxidant activity on guava leaf extract using different solvents based on the value of IC50 resulted from journal review of antioxidant assay on guava leaf. The research used narrative review methods, inclusion and exclusion literature consisting of national journal/International journal of ISSN standard within the last 10-year published from 2010 to 2020. Guava leaf contains antioxidant activity proven by DPPH method, added with ethanol, and methanol. The keywords used to find the results were antioxidant test, free radicals, DPPH method, guava leaves through Google search and Google Scholar. The results confirmed that guava leaf had antioxidant activity. The strongest antioxidant activity possessed by 70% ethanol extract with IC50 0,2 μg/mL. The value of IC50 lies between <10 μg/ mL categorized as the strongest one.

Guava leaf inhibits hepatic gluconeogenesis and increases glycogen synthesis via AMPK/ACC signaling pathways in streptozotocin-induced diabetic rats

Psidium guajava L. is widely used like food and in folk medicine all around the world. Many studies have demonstrated that guava leaves have anti-hyperglycemic and anti-hyperlipidemic activities, among others, and that these activities belong mainly to phenolic compounds, although it is known that phenolic composition in guava tree varies throughout seasonal changes. Andalusia is one of the regions in Europe where guava is grown, thus, the aim of this work was to study the phenolic compounds present in Andalusian guava leaves at different oxidation states (low, medium, and high). The phenolic compounds in guava leaves were determined by HPLC-DAD-ESI-QTOF-MS. The results obtained by chromatographic analysis reported that guava leaves with low degree of oxidation had a higher content of flavonols, gallic, and ellagic derivatives compared to the other two guava leaf samples. Contrary, high oxidation state guava leaves reported the highest content of cyanidin-glucoside that was 2.6 and 15 times higher than guava leaves with medium and low oxidation state, respectively. The QTOF platform permitted the determination of several phenolic compounds with anti-diabetic properties and provided new information about guava leaf phenolic composition that could be useful for nutraceutical production.

Niyoghurt is yoghurt made from coconut milk. Coconut milk has a creamier, softer texture, and provides a distinctive taste compared to cow’s milk. Guava leaf contain a flavonoid compound, quercetin, which is antibacterial. This study aimed to evaluate the effect of the addition of guava leaf extract (Psidium guajava L.) to coconut milk yoghurt (niyoghurt) as a functional food. This study aimed to identify the water content, ash content, fat content, protein content, pH, total lactic acid, antioxidant activities, and hedonic color, flavor, taste, and texture from two types guava leaves (guava leaf and crystal guava leaf) and different concentration of extract (3%, 4%, and 5%). The results of the study showed that types of guava leaves had very significantly effects (P<0.01) on protein content, total lactic acid, hedonic color, texture and taste. The concentration of guava leaf extract had a very significantly effect (P<0.01) on fat content, protein content, total lactic acid, antioxidants, hedonic color, aroma, texture and taste, but did not have a significantly effect (P>0.05) on water content and ash content. The interaction between the type and concentration of guava leaf extract had a very significantly effect (P<0.01) on the hedonic color, texture, aroma and taste.

Diarrhea is a significant health problem, especially in developing countries. Guava leaves (Psidium guajava) have long been used in traditional medicine to treat diarrhea. This study aims to review the literature on the effectiveness of guava leaves in treating diarrhea by focusing on ten aspects: raw material name, raw material content, raw material composition, active substance content, efficacy claims, empirical data, raw material standardization, preclinical test, toxicity test, and clinical trial. The results of several studies show that guava leaves contain tannins, flavonoids, saponins, and essential oils that play a role in the antidiarrheal effect. Preclinical research shows a reduction in the frequency of bowel movements and an increase in stool consistency in animal models. Although empirical claims and preclinical trials support the use of guava leaves as a treatment for diarrhea, more research is still needed regarding the standardization of raw materials, toxicity tests, and clinical trials to ensure its overall efficacy and safety.

Breast and cervical cancers are the leading cause of death in women, and chemotherapy with cytotoxins is the usual treatment. This study evaluated the cytotoxicity of guava leaf (Psidium guajavaL.) extracts as an alternative chemotherapeutic drug. Although many studies related to the cytotoxic effects of guava leaf (Psidium guajavaL.) on cancer cells have been reported, the effects of guava leaf fractions on human breast and cervical cancer cells (T47D, MCF-7, and HeLa) have never been evaluated. Herein, we researched candidate activities of ethanol, ethyl acetate, andn-extracts from guava leaf fractions and their effect on various human cancer cell lines (T47D, MCF-7, and HeLa cells). The cytotoxicity test was carried out using the microtetrazolium assay for all fractions. We confirmed and showed thein vitroantitumor activity of guava leaf (Psidium guajavaL.) fractions in human breast and cervical cancer cells. We found that the effectiveness of anticancer activity increased from ethanol to ethyl acetate ton-hexane fraction. This work underlines the potential ofn-hexane fraction as a chemotherapeutic drug. These novel results have important implications for further isolation, identification, and characterization ofPsidium guajavaL.-based anti-cancer extracts.

The anti-inflammatory activity of 4 plant extracts [guava (Psidium guajava) leaf, capillary wormwood (Artemisia capillaris Thunb.), Chinese goldthread (Coptis chinensis), and dandelion (Taraxacum platycarpum)] was investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Six phenolic compounds (gallic acid, caffeic acid, chlorogenic acid, catechin, quercetin, and baicalin) were analyzed using LC-MS/MS. Guava leaf extracts showed the highest inhibitory effects on LPS-induced nitric oxide (NO, 52.58%) and prostaglandin E2 (PGE2, 43.45%) production. The total phenolic contents (TPC) in guava leaf, capillary wormwood, Chinese goldthread, and dandelion were 426.84, 154.42, 41.73, and 122.04 mg of gallic acid equivalent (GAE)/g of extract, respectively. TPC was positively correlated with the NO-inhibitory effect (r= 0.963, p<0.05) and the PGE2-inhibitory effect (r=0.971, p<0.05) at 30 μg/mL of treatment. The guava leaf extracts contained the highest levels of gallic acid and catechin, while the capillary wormwood extracts contained the highest levels of chlorogenic acid and quercetin.

Guava is a tropical plant found in hot climate areas in South America, Europe, Africa and Asia. Previous research has shown that the phenolic compounds found in guava leaves possess antioxidant and antimicrobial properties. The aim of this study was two‐fold: 1) to determine the antioxidant capacity of guava leaf water, ethanol, and methanol extracts by measuring their total phenol and flavonoid content, and 2) to evaluate the antimicrobial capacity of guava leaf extracts against four different microbes (S. aureus, E. coli, T. mentagrophytes, and T. rubrum). Phenolic content was the highest in the guava leaf water extract, and the flavonoid content in the guava leaf water and ethanol extracts were higher than in the methanol extract. Radical scavenging property, as denoted by 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH•) and 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) levels, was higher in the guava leaf water extracts. Nitric oxide scavenging capacity was not significantly different among the guava leaf extracts. Ethanol, methanol, and water guava leaf extracts significantly inhibited microbial growth, with the ethanol guava leaf extract showing the highest activity against the S. aureus and E. coli. This suggests a relationship between the phenolic content and the antioxidant activity, as well as between the flavonoid content and antimicrobial activity of guava leaf extracts.

Aim: The present aim is to evaluate the anti-diabetic effect of aqueous extract of guava (Psidium guajava) leaf using rat model of diabetes induced by streptozotocin. In addition, the effect of this extract on liver and kidney functions induced in rat model of diabetes were investigated. Material and Methods: Rats were divided randomly into: control group, rat model of diabetes induced by streptozotocin, rat model of diabetes treated with aqueous extract of guava leaf, rat model of diabetes treated with glibenclamide and rat model of diabetes treated with aqueous extract of guava leaf plus glibenclamide. Result: In the present rat model of diabetes a significant decrease in the serum insulin level and a significant increase in glucose level were detected. Streptozotocin induced a significant increase in the activities of AST, ALT, ALP and a significant increase in the levels of bilirubin, urea, creatinine and uric acid. In addition histopathological and immunological changes were detected in the pancreatic tissue. The present data revealed that aqueous extract of guava leaf improved the reduced insulin level and the high glucose level induced by streptozotocin. This was associated with an improvement in the changes in the liver and kidney functions. Loss of body weight gain induced by streptozotocin was alleviated by guava leaf extract, glibenclamide or both. Conclusion: According to the present findings it could be concluded that the aqueous extract of guava leaf has a potent anti-hyperglycemic effect on rat model of diabetes induced by streptozotocin with hepatic and renal protective effects.

Guava (Psidium guajava L.) leaf protease activity enriched by controlled-stress and putrescine application