Development and Validation of a Simple, Sensitive Fluorescent Method for Eurycomanone Quantification in Tongkat Ali Using Nitrogen-Doped Carbon Quantum Dots and Box-Behnken Design Optimization

Eurycoma longifolia Jack, commonly known as Tongkat Ali, is a medicinal herb traditionally valued for its aphrodisiac properties, with eurycomanone being its principal bioactive quassinoid. This study introduces a novel, cost-effective method for the sensitive detection of eurycomanone using nitrogen-doped carbon quantum dots (N-CQDs) as a fluorescent probe. The spectral characteristics of the probe were carefully analyzed using UV-vis and fluorescence spectrophotometric techniques, and the sensing mechanism was investigated through Stern-Volmer and thermodynamic studies, revealing a static quenching interaction. A Box-Behnken design of experiment was applied to optimize the sensing conditions including pH, incubation time, and probe concentration, ensuring high sensitivity and robustness. A reduced quadratic model was found significant (p value > 0.0001) with pH and N-CQDs concentration being the most influential factors. The method was rigorously validated following ICH guidelines displaying excellent linearity in the range of 0.25-6.0 μg/mL, high sensitivity (LOD 0.067 μg/mL), and high accuracy and precision (RSD < 1.5%). The proposed technique was successfully applied to the analysis of real Tongkat Ali samples, demonstrating its practical utility in herbal analysis. The results showed good agreement with reported chromatographic methods, positioning the technique as a promising alternative to conventional analytical methods.

Metabolome classification of Tongkat Ali (Eurycoma longifolia jack) and its commercial products via UHPLC-QTOF-MS-MS and its protective effect against 5-flurouracil-Induced testicular toxicity in male rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tongkat Ali (Eurycoma longifolia Jack) is a chief herbal medicine that is well recognized for its aphrodisiac properties, available in various commercial products worldwide.

AIM OF THE STUDY

The aim of this work is to identify the different classes of secondary metabolites present in Tongkat Ali commercial products versus authenticated root, and to assess its root extract mitigative effect against 5-flurouracil (5FU)-induced testicular toxicity.

MATERIALS AND METHODS

High-resolution UHPLC-QTOF-MS/MS metabolites analysis was utilized on the ethanolic Tongkat Ali extract (TAE) parallel to three Mlayasian commercial products, followed by a multivariate data analysis to understand the variability among UHPLC-MS metabolites datasets. Adult male rats were treated with 5-Fluorouracil (5FU) ± Tongkat Ali extract. Semen parameters, serum testosterone, LH, and FSH, and testicular oxidative stress biomarkers like malondialdehyde (MDA) levels, Nuclear factor kappa B (NF-κB) and erythroid 2-related factor 2 (Nrf2) were analyzed.

RESULTS

The main categories of secondary metabolites identified through UHPLC-MS/MS profiling were quassinoids, alkaloids, fatty acids, lignans and coumarins. Long Jack Plus® ELP-2 clustered alongside authentic roots ELR on the negative side, while Naturelle® ELP-1 and Nu-Prep-LEAKI® ELP-3 were positioned on the opposite side. The OPLS-DA model was used to identify markers for preparations from authentic roots, with commercial products enriching in ailanthone epoxide. In vivo results showed that 5FU reduced sperm parameters by 42%, while TAE improved sperm quality by 35-43% and 58-74% at dose of 400 and 800 mg/kg, respectively. Testosterone, reduced by 74% with 5FU, increased 2.3- to 3.2-fold with TAE. TAE also reduced MDA by 31-62%, NF-κB by 32-55% and increased Nrf2 by 1-2 folds.

CONCLUSION

The manuscript presents a comparative metabolomics study and in vivo investigation into the potential of Tongkat Ali root to improve testicular function in male rats intoxicated with 5FU, an area not previously explored. Further research is required to understand the mechanisms.

Simultaneous quantification of eurycomanone, epimedin C and icariin in film coated tablets containing Radix Eurycomae longifoliae extract and Herba Epimedii extract using HPLC – DAD

Introduction. This study aimed at developing an HPLC-DAD method for simultaneous determination of eurycomanone (EU), epimedin C (EC) and icariin (IC) in EE tablets containing Radix Eurycomae longifoliae extract and Herba Epimedii extract (EE tablets).

Methods. Several HPLC conditions (detection wavelength, mobile phase) and sample preparation conditions (type of solvent, ratios of tablet powder and solvent) were investigated.

Results. The optimized HPLC condition employed a Shim-Pack RP18 column and a detection wavelength of 254 nm. The mobile phase consisted of acetonitrile and water containing 0.1% H3PO4 in gradient elution. The method was selective, linear, precise (RSD &lt; 2%) and accurate with recoveries in the range of 98.51–104.58% for EU, 96.22–104.80% for EC and 97.50–104.96% for IC.

Conclusion. The method for simultaneous quantification of EU, EC and IC in EE tablets by HPLC – DAD was developed and validated for the first time and could be applied for quality control of EE tablets.

Assessing product adulteration of Eurycoma longifolia (Tongkat Ali) herbal medicinal product using DNA barcoding and HPLC analysis

CONTEXT

Eurycoma longifolia Jack (Simaroubaceae) commonly known as Tongkat Ali is one of the most important plants in Malaysia. The plant extracts (particularly roots) are widely used for the treatment of cough and fever besides having antimalarial, antidiabetic, anticancer and aphrodisiac activities.

OBJECTIVES

This study assesses the extent of adulteration of E. longifolia herbal medicinal products (HMPs) using DNA barcoding validated by HPLC analysis.

MATERIALS AND METHODS

Chloroplastic rbcL and nuclear ITS2 barcode regions were used in the present study. The sequences generated from E. longifolia HMPs were compared to sequences in the GenBank using MEGABLAST to verify their taxonomic identity. These results were verified by neighbor-joining tree analysis in which branches of unknown specimen are compared to the reference sequences established from this study and other retrieved from the GenBank. The HMPs were also analysed using HPLC analysis for the presence of eurycomanone bioactive marker.

RESULTS

Identification using DNA barcoding revealed that 37% of the tested HMPs were authentic while 27% were adulterated with the ITS2 barcode region proven to be the ideal marker. The validation of the authenticity using HPLC analysis showed a situation in which a species which was identified as authentic was found not to contain the expected chemical compound.

DISCUSSION AND CONCLUSIONS

DNA barcoding should be used as the first screening step for testing of HMPs raw materials. However, integration of DNA barcoding with HPLC analysis will help to provide detailed knowledge about the safety and efficacy of the HMPs.

Development of a selective HPLC-DAD/ELSD method for the qualitative and quantitative assessment of commercially available Eurycoma longifolia products and plant extracts

Aqueous extracts of the roots of Eurycoma longifolia are traditionally used to improve sexual performance, to treat infertility and other sexual dysfunctions but also to increase muscle strength. Nowadays, many different products are commercially available which are promoted as E. longifolia extracts and claim to possess beneficial aphrodisiac effects. Since such herbal aphrodisiac preparations have been recently the target of fraudulent product counterfeiting and because eurycomanone, one of the main quassinoids of E. longifolia, is suspected to possess toxic effects at higher concentrations, a highly selective HPLC-DAD/ELSD method has been established to analyze commercially available products and extracts of plant material. The presented method was established by the use of a mixture of 27 reference compounds for qualitative issues and fully validated according to the ICH guidelines for the quantification of three quassinoides: laurycolactone A, longilactone, and eurycomanone. The calibration curves of these showed a linearity over a range of 0.05 to 1.0mg/ml, with a regression coefficient not lower than R²=0.9969. The inter-day and intra-day precision (indicated as relative standard deviation) of the developed method was <2.9%. The recovery ranged from -3.3% to +6.0%. Eight randomly purchased products have been analyzed with this method, but only five of them contained E. longifolia compounds in detectable amounts. The concentration of eurycomanone in these products varied from 0.22±0.002mg eurycomanone per capsule to 1.84±0.08mg corresponding to a maximal recommended daily intake of 0.76±0.02 to 31.90±0.21mg.

Review: DNA Barcoding and Chromatography Fingerprints for the Authentication of Botanicals in Herbal Medicinal Products

In the last two decades, there has been a tremendous increase in the global use of herbal medicinal products (HMPs) due to their claimed health benefits. This has led to increase in their demand and consequently, also, resulted in massive adulteration. This is due to the fact that most of the traditional methods cannot identify closely related species in a process product form. Therefore the urgent need for simple and rapid identification methods resulted in the discovery of a novel technique. DNA barcoding is a process that uses short DNA sequence from the standard genome for species identification. This technique is reliable and is not affected by external factors such as climates, age, or plant part. The difficulties in isolation of DNA of high quality in addition to other factors are among the challenges encountered using the DNA barcoding in the authentication of HMP. These limitations indicated that using DNA barcoding alone may ineffectively authenticate the HMP. Therefore, the combination of DNA barcoding with chromatographic fingerprint, a popular and generally accepted technique for the assessment and quality control of HMP, will offer an efficient solution to effectively evaluate the authenticity and quality consistency of HMP. Detailed and quality information about the main composition of the HMPs will help to ascertain their efficacy and safety as these are very important for quality control.

Development of Chromatographic Fingerprints of Eurycoma longifolia (Tongkat Ali) Roots Using Online Solid Phase Extraction-Liquid Chromatography (SPE-LC)

E. longifolia is attracting interest due to its pharmacological properties and pro-vitality effects. In this study, an online SPE-LC approach using polystyrene divinyl benzene (PSDVB) and C18 columns was developed in obtaining chromatographic fingerprints of E. longifolia. E. longifolia root samples were extracted using pressurized liquid extraction (PLE) technique prior to online SPE-LC. The effects of mobile phase compositions and column switching time on the chromatographic fingerprint were optimized. Validation of the developed method was studied based on eurycomanone. Linearity was in the range of 5 to 50 µg∙mL(-1) (r² = 0.997) with 3.2% relative standard deviation of peak area. The developed method was used to analyze 14 E. longifolia root samples and 10 products (capsules). Selected chemometric techniques: cluster analysis (CA), discriminant analysis (DA), and principal component analysis (PCA) were applied to the fingerprint datasets of 37 selected peaks to evaluate the ability of the chromatographic fingerprint in classifying quality of E. longifolia. Three groups were obtained using CA. DA yielded 100% correlation coefficient with 19 discriminant compounds. Using PCA, E. longifolia root samples were clearly discriminated from the products. This study showed that the developed online SPE-LC method was able to provide comprehensive evaluation of E. longifolia samples for quality control purposes.

Isolation, Characterization, Crystal Structure Elucidation of Two Flavanones and Simultaneous RP-HPLC Determination of Five Major Compounds from Syzygium campanulatum Korth

Two flavanones named (2S)-7-Hydroxy-5-methoxy-6,8-dimethyl flavanone (1), (S)-5,7-dihydroxy-6,8-dimethyl-flavanone (2), along with known chalcone, namely, (E)-2ʹ,4ʹ-dihydroxy-6ʹ-methoxy-3ʹ,5ʹ-dimethylchalcone (3) and two triterpenoids, namely, betulinic and ursolic acids (4 and 5), were isolated from the leaves of Syzygium campanulatum Korth (Myrtaceae). The structures of compounds (1 and 2) were determined on the basis of UV-visible, FTIR, NMR spectroscopies and LC-EIMS analytical techniques. Furthermore, new, simple, precise, selective, accurate, highly sensitive, efficient and reproducible RP-HPLC method was developed and validated for the quantitative analysis of the compounds (1–5) from S. campanulatum plants of five different age. RP-HPLC method was validated in terms of specificity, linearity (r² ≤ 0.999), precision (2.0% RSD), and recoveries (94.4%–105%). The LOD and LOQ of these compounds ranged from 0.13–0.38 and 0.10–2.23 µg·mL⁻¹, respectively. Anti-proliferative activity of isolated flavanones (1 and 2) and standardized extract of S. campanulatum was evaluated on human colon cancer (HCT 116) cell line. Compounds (1 and 2) and extract revealed potent and dose-dependent activity with IC₅₀ 67.6, 132.9 and 93.4 µg·mL⁻¹, respectively. To the best of our knowledge, this is the first study on isolation, characterization, X-ray crystallographic analysis of compounds (1 and 2) and simultaneous RP-HPLC determination of five major compounds (1–5) from different age of S. campanulatum plants.