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Today, there is increasing interest in discovering new bioactive compounds derived from ethnomedicine. Preparations of guava (Psidium guajava L.) leaves have traditionally been used to manage several diseases. The pharmacological research in vitro as well as in vivo has been widely used to demonstrate the potential of the extracts from the leaves for the co-treatment of different ailments with high prevalence worldwide, upholding the traditional medicine in cases such as diabetes mellitus, cardiovascular diseases, cancer, and parasitic infections. Moreover, the biological activity has been attributed to the bioactive composition of the leaves, to some specific phytochemical subclasses, or even to individual compounds. Phenolic compounds in guava leaves have been credited with regulating blood-glucose levels. Thus, the aim of the present review was to compile results from in vitro and in vivo studies carried out with guava leaves over the last decade, relating the effects to their clinical applications in order to focus further research for finding individual bioactive compounds. Some food applications (guava tea and supplementary feed for aquaculture) and some clinical, in vitro, and in vivo outcomes are also included.

Despite their effectiveness, synthetic preservatives are often associated with adverse health effects, which has led to growing interest in natural alternatives. This study evaluated the antimicrobial activity of an ethanolic extract of Psidium guajava L. leaves incorporated into a shampoo formulation. The ethanolic extract of Psidium guajava L. leaves was tested at concentrations of 0.5%, 2.5%, 5%, 7.5%, and 10% (w/w) under accelerated conditions for three months. Phytochemical screening and HPLC analysis were conducted to identify key bioactive compounds (including phenols, flavonoids, and terpenoids), antimicrobial efficacy testing, and stability testing (such as pH, viscosity, density, and color) were evaluated. At concentration 10%, extract completely inhibited microbial growth over a 28-day period, in comparison with chemical preservatives. Stability testing conducting at accelerated temperatures (40 °C/75% RH) for three months confirmed the physical stability of the formulation and the chemical integrity of ketoconazole. Preservative efficacy tests, performed accordance with USP/BP guidelines against Escherichia coli , Pseudomonas aeruginosa , Staphylococcus aureus , Candida albicans , and Aspergillus brasiliensis , demonstrated that the extract reduced microbial counts beyond USP/BP acceptance criteria, achieving total inhibition of all strains within 28 days. Chemical and biological tests confirmed formulation stability and efficacy over a three-months period. The findings suggest that P. guajava L. extract is a promising natural preservative; however, further studies are needed to assess its long-term stability.

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.

Guava ( Psidium guajava L.), a rich source of nutrients, is an important tropical and subtropical fruit of the Myrtaceae family and exhibits magnificent diversity. Genetic diversity analysis is the first step toward the identification of parents for hybridization, genetic mapping, and molecular breeding in any crop species. A diversity analysis based on whole-genome functional markers increases the chances of identifying genetic associations with agronomically important traits. Therefore, here, we sequenced the genome of guava cv. Allahabad Safeda on an Illumina platform and generated a draft assembly of ~304 MB. The assembly of the Allahabad Safeda genome constituted >37.95% repeat sequences, gene prediction with RNA-seq data as evidence identified 14,115 genes, and BLAST n/r, Interproscan, PfamScan, BLAST2GO, and KEGG annotated 13,957 genes. A comparative protein transcript analysis of tree species revealed the close relatedness of guava with Eucalyptus. Comparative transcriptomics-based SSR/InDel/SNP-PCR ready genome-wide markers in greenish-yellow skinned and white fleshed-Allahabad Safeda to four contrasting cultivars viz apple-color-skinned and white-fleshed-Lalima, greenish-yellow-skinned and pink-fleshed-Punjab Pink, purple-black-skinned and purple-fleshed-Purple Local and widely used rootstock-Lucknow-49 were developed. The molecular markers developed here revealed a high level of individual heterozygosity within genotypes in 22 phenotypically diverse guava cultivars. Principal coordinate, STRUCTURE clustering, and neighbor-joining-based genetic diversity analysis identified distinct clusters associated with fruit skin and flesh color. The genome sequencing of guava, functional annotation, comparative transcriptomics-based genome-wide markers, and genetic diversity analysis will expand the knowledge of genomes of climacteric fruits, facilitating trait-based molecular breeding and diversifying the nutritional basket.

Biomass waste, as raw material for renewable energy, is an attractive alternative since it does not compete with human food supply. An emerging alternative for its treatment is supercritical water gasification (SCWG), due to the high moisture content of some types of biomass. On this regards, guava fruit (Psidium guajava L.) is one of the most wasted agro-food products in Mexico. This motivated us to evaluate gasification of guava waste on dry biomass base under supercritical water conditions for the first time, with the aim of analyzing the impact of moderate temperatures and feed ratios as reaction parameters on gas products. Temperature was varied in the range of 673.15–773.15 K and using a batch reactor loaded with biomass:water (B:W) mass ratios of 1:1, 1:4, and 1:6. Furthermore, the obtained solid, liquid, and gas phase products were characterized. Hydrogen (H2), carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10) were identified in gas phase and quantified by means of a gas chromatograph equipped with a TCD detector. Liquid and solid phase products were subjected to Fourier Transform Infrared spectroscopy analyses. This preliminary research indicated that high temperature operation and high biomass:water mass ratio enhanced gas yields (mol/kg) of about 4.137 for CH4, 6.705 for CO2, and 7.743 for H2; whereas the selectivity and gas efficiency for hydrogen was 65.26% and 58.94%, respectively.

AbstractGuava (Psidium guajava L.) is a nutritionally rich fruit exhibiting white, yellow, pink, and purple variants for pulp color. To understand the genetic and molecular basis of pulp color, 35 F1s obtained from colored/white crosses and their parents were characterized for pulp color. Black guava (BG) had a rare peel and pulp color with the least amount of lycopene, similar to white-pulped parental genotypes. BG/white crosses gave rise to only white progenies while pink/white crosses segregated into pink, yellow, and white F1s. This confirmed that the pigment responsible for color in BG is not lycopene and the pink-pulped parents are heterozygous for the gene(s) governing pulp color. Additional 74 F1s-generated confirmed that the white pulp color inheritance is homozygous recessive in guava. Pigment composition analysis of all the colored F1s (18/ 35) and the three colored parents revealed that lycopene was present in all the 21 samples but at a wider range (0.16–22.56 mg/100 g). Zeaxanthin was also present in all the samples except two F1s. On the contrary, lutein was found only in five F1 progenies but not in any of the pink-pulped parents. Overall, the pigment composition analysis of F1s and their respective parents revealed that the pulp color in guava is a polygenic trait. We identified 12 distinct SNPs between pink and white-pulped guava genotypes in the PSY1 gene. These variations can be used to develop molecular markers for marker assisted selection of pulp color in guava breeding.

Several drugs now employed in cancer therapy were discovered as a result of anticancer drug research based on natural products. Here, we reported the in vitro antioxidant and anticancer activity followed by in silico anticancer and estrogen-like activity of Psidium guajava L. essential oil against ER-α receptors which lead to potential inhibitory action against breast cancer pathways. Methods: The bioactive compounds in guava essential oil were screened using gas chromatography–mass spectrometry (GC-MS). Similarly, the antioxidant properties of the extracted oil were evaluated using 2,2-Diphenyl-1-picrylhydrazyl scavenging assay. Furthermore, the in vitro anticancer activity of guava oil was observed through the MTT assay and an in silico molecular docking experiment was also carried out to ensure that they fit into the estrogen receptors (ERs) and possess anticancer potential. Results: The GC–MS profile of the essential oil revealed the presence of 17 chemicals, with limonene (51.3%), eucalyptol (21.3%), caryophyllene oxide (6.2%), caryophyllene (5.6%), and nerolidol (4.5%) occupying more than one-third of the chromatographic spectrum zone. Guava leaves’ essential oil (EO) inhibited DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and exhibited concentration dependent free radical scavenging activity, acting as a potent antioxidant with an IC50 value of 29.3 ± 0.67 µg/mL. The outcome of the MTT assay showed that the extracted guava oil had nearly the same efficacy against breast and liver cancer cells at a low concentration (1 µg/mL), giving 98.3 ± 0.3% and 98.5 ± 0.4% cell viability against HepG2 at 1 µg/mL, respectively. When the concentration of essential oil was increased, it showed a small reduction in the percentage of viable cells. While conducting an in silico study of all the screened compounds, the potential for hydroxycaryophyllene, caryophyllene, caryophyllene oxide, humulene, terpineol, and calamenene to inhibit tumor growth was bolstered due to a resemblance to 4-hydroxytamoxifen, thereby implying that these compounds may act as selective estrogen receptor modulators (SERMs). The ADME analysis of the compounds indicated above revealed that they exhibit excellent drug likeness properties and follow the Lipinski rule of five. Conclusions: Consequently, they have a substantial anticancer therapeutic potential and can be used for novel drug discovery in the effort to minimize the global burden of breast cancer.

Psidium guajava L. (Myrtaceae) is a neotropical species whose leaf extracts demonstrate efficacy against cutaneous and mucosal inflammation and ulceration. This study aimed to prepare and characterize aqueous extracts of P. guajava leaves (EAPG) and incorporate them into chitosan nanoparticles for topical delivery to the oral mucosa. The extract was obtained by infusion, and its marker compound was quantified by a chromatographic method. EAPG exhibited antioxidant activity (IC50: 6.35–7.01 µg/mL in DPPH•; FRAP: 14.42–17.83 µg/mL ≈ 60 µM Fe2+) and anti-inflammatory potential by modulating the expression of IL-6. It also showed antifungal activity against Candida species. Nanoparticles loaded with EAPG had a mean diameter of 899.8 ± 10.8 nm, PdI 0.22 ± 0.03, Zeta potential +32.4 ± 2.3 mV, pH 5.0, and 62 ± 1% encapsulation efficiency. They remained stable for 30 days. In an ex vivo topical application, EAPG nanoparticles delivered 415.17 ± 71.7 µg/cm2 of marker to the oral mucosa, eight times more than free EAPG (p < 0.05). These results suggest that chitosan-based EAPG nanoparticles are a promising strategy for topical treatment of mucosal disorders.

The search for novel antimicrobial agents in Endodontics is constant to overcoming persistent infections. L. is a medicinal plant little explored in Endodontics. The aim of this study was to produce hydroethanolic extract of L. and to evaluate its phytochemical composition, antimicrobial and antibiofilm action against standard and clinical strains of and , and cytotoxicity and genotoxicity on human keratinocyte cultures (HaCaT cells). The findings provide new insights into the potential of as an alternative endodontic antimicrobial agent, contributing to the development of more effective and biocompatible therapeutic strategies. hydroethanolic extract was produced using young leaves of guajava and extracted using absolute ethanol and ultrapure water in a ratio (30 g:100 mL). The solid soluble, total flavonoid and total phenols content were determined. The chemical composition was determined high-performance liquid chromatography (HPLC) analysis, then the free radical suppressive activity was assessed by determining the IC value, indicating the concentration required to eliminate 50% of free radicals. Later, the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the extract was evaluated against the strains using clinical and laboratory standards institute (CLSI) guidelines (M27-S4 and M7-A9). Then, the antibiofilm activity was evaluated MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. Finally, the cytotoxicity of the extract was evaluated Alamar Blue assay, and the genotoxicity micronucleus assay on human keratinocyte cultures (HaCaT cells). Data were analyzed using ANOVA and Tukey's test or Kruskal-Wallis and Dunn's test. The soluble solids content in the extract was 3.35%. Using the quercetin standard curve, the total flavonoid concentration was 0.130 ± 0.110 mg/mL. In addition, using standard curve for phenolic acids, the total phenolic concentration was 1.770 ± 1.540 mg/mL. HPLC analysis revealed peaks of rutin, quercetin and kaempferol as major flavonoids in the L. extract. The extract demonstrated notable antioxidant activity, with an IC value of 10.39 µg/mL. The MMC values ranged 1.04-8.37 mg/mL. The extract at 8.37 mg/mL was effective in reducing the biofilms of standard and clinical strains of and after 10 min. Cytotoxicity analysis revealed that all tested concentrations exhibited relatively low toxicity toward HaCaT cells. Genotoxicity assessment the micronucleus assay indicated minimal DNA damage at all tested concentrations. Overall, L. hydroethanolic extract at 8.37 mg/mL is the most effective concentration in reducing the biofilm of the standard and clinical strains of and , while maintaining biocompatibility with HaCaT cultures.

This study aimed to reveal the lipid composition and distribution and characterize the lipid metabolism profile in the three distinct parts of four guava varieties with varying textures and colors using liquid chromatography–electrospray ionization–tandem mass spectrometry. The four varieties, collected from a guava cultivation base in Danzhou City, Hainan Province, were “Zhenzhu” (white-fleshed hard-crispy guava, YBSL), “Bendi” (white-fleshed soft-waxy guava, RBSL), “Xiguahong” (red-fleshed hard-crispy guava, YHSL), and “Hongxin” (red-fleshed soft-waxy guava, RHSL). A total of 8242 lipids were detected, which were classified into four categories and 20 subcategories. Glycerolipids and glycerophospholipids are the most abundant types of lipids in guava. The lipid composition showed significant differences between hard-crispy and soft-waxy guavas. The red-fleshed guava varieties had 98, 57, and 96 differential lipid metabolites, whereas white-fleshed varieties had 68, 108, and 41 lipid metabolites in the epicarp, mesocarp, and endocarp, respectively. Moreover, comparative analysis of hard-crispy versus soft-waxy guavas with different colors revealed common differential lipids in the epicarp (29), mesocarp (21), and endocarp (18). The common differential lipids, including phosphatidylcholine (PC) (16:0/18:1), PC (18:1/18:1), and phosphatidylethanolamine (PE) (18:1/18:2), were found to be upregulated across all fruit parts, with greater abundance in soft-waxy guavas. They were mainly enriched in metabolic pathways associated with glycerophosphocholine and glycerophosphoethanolamine. These differential lipids may serve as potential biomarkers for evaluating guava quality. This study unveiled the lipid distribution and metabolic variations among different guava varieties. It also established a scientific foundation for improving guava varieties and implementing quality control measures.