| Pure Hypocrellin includes hypocrellin A (HA) and hypocrellin B (HB). At present, it is widely used in clinical not completely isolated and contains some of the other ingredients or impurities in crude Hypocrellin. For a variety of skin diseases clinical findings, it must work in light therapy to obtain good results. However, the therapeutic mechanism has not been understood. Thus in the treatment, the skin applied drug is just irradiated with broad-band light source apply. The control of drug concentration and light-band systems do not have the system research, it will inevitably affect the drug efficacy and further broaden scope of application. In this article, by studying the spectra characteristics and photophysical mechanism of the different states of Hypocrellin, it will offer experimental and theoretical basis for Hypocrellin clinical applications.The absorption and fluorescence spectra of three states of Hypocrellin(including pure Hypocrellin, crude Hypocrellin and Hypocrellin ointment ) are measured by the Fiber Optic Spectrometer system and Roper Scientific SP-2558 multifunctional spectrometer system. The origin software was used to process the data. Then we discuss the mechanism of spectra in the aspect of theoretical analysis and experimental results. The result shows that:1. The absorption spectra of crude Hypocrellin can be broadly divided into two regions:â… area (range 200 ~ 336nm) andâ…¡area (range 336-650nm). Crude Hypocrellin in different solvents have a strong absorption spectrum inâ… a rea, and the spectral peak form has big difference. But, this band of light has a great damage to skin cell, therefore we propose to avoid or reduce choose the band in clinic.2. The absorption spectrums of different states of Hypocrellin all have 4 peaks in theâ…¡area. And, Hypocrellin shows the stronggest absorbance in the blue area range 430 ~ 490nm, which is also the effective band in clinical light therapy, so we think it will be the very effective band to promote the curative effect of Hypocrellin.3. Different states Hypocrellin solution fluorescence spectra have only one fluorescence peak at around 610nm, which is different with pure HA and HB. Though origin software was used to process the data, we conclude the fluorescence of Hypocrellin is mainly contributed by HA and HB, but because of fluorescence resonance energy transfer between HA and HB leads the contribution rate of HB increase, it is bring about the red-shift.4. The excitation spectrum peak of Hypocrellin is in the blue area absorption band, and the fluorescence spectra are mainly located at 600 ~ 650nm. On the basis of clinical reports, we believe that it is the main reason for Hypocrellin must be used cooperated with light.5. Different concentration shows different fluorescence intensity, which suggest that we can choose the right concentration according the clinical condition of patients, in order to get better curative effect.6. The maximum fluorescence intensity of crude Hypocrellin is slightly lower than pure Hypocrellin because of the effective concentration. But, the fluorescence intensity of Hypocrellin ointment is almost same with the Crude under the case of having very lower photosensitive ingredients concentration, which maybe has a practical significance in the clinical treatment with enhancing phototherapy effect.
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