The broadcast is a fundamental operation in computer and communication networks. We study broadcast in multiradio multichannel multi-hop wireless networks. Suppose through configuration, each node is already assigned with a transmission power level and a set of radio channels for receiving and forwarding data. Our problem is to select a forward scheme for broadcasting from a given source node and to minimize total energy consumption. This is a known NP-hard minimization problem. In this paper, we construct a polynomial-time (1.35 + ε)(1+ln(n-1))-approximation algorithm where n is the number of nodes in given network and ε is any positive constant. We also show that there is no polynomial-time (ρ ln n)-approximation for 0 < ρ < 1 unless NP ⊆ DTIME(n O(log log n)).