Commonly used herbal medicines in the United States: a review
Herbal medicines are widely used in the United States, with approximately one quarter of adults reporting use of an herb to treat a medical illness within the past year. Herbs contain complicated mixtures of organic chemicals, the levels of which may vary substantially depending upon many factors related to the growth, production, and processing of the herbal product. While many manufacturers attempt to provide products with consistent levels of suspected active ingredients through a process known as standardization, this technique has uncertain effects on the safety and efficacy of the final product. Herbs are considered to be dietary supplements in the United States and therefore are subjected to a very limited form of regulation and oversight. Although herbs are often believed to be “natural” and therefore safe, many dangerous and lethal side effects have recently been reported, including direct toxic effects, allergic reactions, effects from contaminants, and interactions with drugs and other herbs. Of the ten most commonly used herbs in the United States, systematic reviews have concluded that only four are likely to be effective, and there is very limited evidence to evaluate the efficacy of the approximately 20,000 other available herbal products. Because herbs may contain potent bioactive substances and are often marketed to treat specific diseases, many have argued that they should be subject to more stringent regulation, similar to over-the-counter drugs. To improve the safety and consistency of herbs, additional research is needed to define the pharmacology, stability, and bioavailability of these products. 
Quality control of herbal medicines
Different chromatographic and electrophoretic techniques commonly used in the instrumental inspection of herbal medicines (HM) are first comprehensively reviewed. Chemical fingerprints obtained by chromatographic and electrophoretic techniques, especially by hyphenated chromatographies, are strongly recommended for the purpose of quality control of herbal medicines, since they might represent appropriately the “chemical integrities” of the herbal medicines and therefore be used for authentication and identification of the herbal products. Based on the conception of phytoequivalence, the chromatographic fingerprints of herbal medicines could be utilized for addressing the problem of quality control of herbal medicines. Several novel chemometric methods for evaluating the fingerprints of herbal products, such as the method based on information theory, similarity estimation, chemical pattern recognition, spectral correlative chromatogram (SCC), multivariate resolution, etc. are discussed in detail with examples, which showed that the combination of chromatographic fingerprints of herbal medicines and the chemometric evaluation might be a powerful tool for quality control of herbal products. 
Quality of herbal medicines: Challenges and solutions
The popularity of herbal medicines has risen worldwide. This increase in usage renders safety issues important. Many adverse events of herbal medicines can be attributed to the poor quality of the raw materials or the finished products. Different types of herbal medicines are associated with different problems. Quality issues of herbal medicines can be classified into two categories: external and internal. In this review, external issues including contamination (e.g. toxic metals, pesticides residues and microbes), adulteration and misidentification are detailed. Complexity and non-uniformity of the ingredients in herbal medicines are the internal issues affecting the quality of herbal medicines. Solutions to the raised problems are discussed. The rigorous implementation of Good Agricultural and Collection Practices (GACP) and Good Manufacturing Practices (GMP) would undoubtedly reduce the risk of external issues. Through the use of modern analytical methods and pharmaceutical techniques, previously unsolved internal issues have become solvable. Standard herbal products can be manufactured from the standard herbal extracts. 
Microbial Contamination of Some Antidiabetic Herbal Preparations Available in Bangladesh
Herbal Medicines (HM) are being used in our country for a long time but the type and load of the microbial agents has not been isolated in locally produced finished products of HM. The present study was designed to assess the microbial load, genus & species of the microbes contaminating with HM. Seven different Antidiabetic Herbal Preparations (ADHPs) were purchased randomly and analyzed for microbial contaminants. Blood agar, Mac Conkey agar, Chocolate agar and Saboraud’s dextrose agar were used (Oxoid) for culturing and isolation of bacteria and fungus. Identification of organisms were done as standard ways. Total aerobic bacterial plate count was done as per the method of Brown, Poxton and Wilkinson. Out of 07 antidiabetic solid and liquid samples, except ADHP-3, Bacillus subtilis (3.5 – 4.0 x 104 cfu/g) was isolated from solid ADHPs and Enterococcus spp. (1.0×104 cfu/ml) was isolated from liquid ADHP, but all samples were free from fungi (yeasts and moulds). However presence of bacteria in these samples indicates the possibility of increased number of bacteria. So, the sample should be handled in any step maintaining standard sterility of the environment, instrument and involved personnel. The result of present study showed the contamination rate within tolerable level but the presence of bacteria in these samples was not desirable. 
Phytochemical, Physicochemical and Chromatographic Profiling in Quality Control Systems for Select Herbal Medicines (Conavir and Niprd-AM1)
Background: Conavir, an immunostimulant from aerial parts of Andrographis paniculata (AP) and Niprd-AM1, an antimalarial from roots of Nauclea latifolia (NL), are dry water extracts for capsulation. AP and NL have been in use in Asia and Africa for centuries.
Purpose: The study aimed to ascertain the criteria for quality assured production of Conavir and Niprd-AM1.
Experimental Details: Procedures of World Health Organization (WHO) were applied to evaluate quality parameters of AP/Conavir and NL/Niprd-AM1.
Results and Discussion: Conavir is granular, greenish brown, intensely bitter and practically odourless. Tests on AP and Conavir revealed alkaloids, saponins, tannins and terpenoids, but cardiac and cyanogenic glycosides (considered toxic) were not detected. Normal phase TLC of AP and Conavir yielded 5 principal spots each, while the reverse phase TLC yielded 6. HPLC fingerprints of AP, Conavir and a reference standard were reproducible but differed from each other. The GC-MS data of Conavir were consistent with the phytochemical profile of AP. Effect of storage suggested that both AP and Conavir were stable for up to 21 months or more. Niprd-AM1 is granular, yellowish brown and faintly aromatic, with an exciting bitter taste. Both NL and Niprd-AM1 contained alkaloids, saponins, flavonoids and terpenoids, but cardiac and cyanogenic glycosides were not detected. Normal phase TLC of NL yielded 9 principal spots, while Niprd-AM1 yielded 5, but the reverse phase TLC yielded 9 for each. HPLC fingerprints of NL, Niprd-AM1 and a reference standard were reproducible but differed from each other. The GC-MS data of Niprd-AM1 were consistent with the phytochemical profile of NL. Most of the quality variables of NL and Niprd-AM1 remained unchanged up to the 39th month of storage.
Conclusion: The results are consistent with NIPRD’s intention to file for the registration of Conavir and Niprd-AM1 for use in Nigeria. 
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 Ahmed, M.R., Asna, S.M.Z.H., Khan, M.S.H., Rokeya, B., Mosihuzzaman, M. and Sayeed, M.A., 2016. Microbial Contamination of Some Antidiabetic Herbal Preparations Available in Bangladesh. European Journal of Medicinal Plants, pp.1-5.
 Ameh, S., Abubakar, M., Ambi, A., Ikokoh, P., Obodozie, O., Garba, M. and Cocker, H., 2013. Phytochemical, physicochemical and chromatographic profiling in quality control systems for select herbal medicines (Conavir and Niprd-AM1). Journal of Pharmaceutical Research International, pp.13-36.